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Natural inorganic gem materials · Mineral / gemstone variety · Natural; treatment common (require certificate to distinguish)

Emerald

A green variety of Beryl coloured by chromium or vanadium; oiling and filling treatments are extremely common and must be disclosed in the name. This page compares how the major standards and institutions name it, what must be disclosed when selling it, whether it can be worn every day, how it is treated and identified, and which source each conclusion comes from.

Price, rarity and origin are outside the scope of this wiki.

Edited by RalphReviewed by JuneLast updated 2026-10-12Who maintains this page

FAQCare and wear

Questions people ask about Emerald

Every sentence below is followed by the registered fact it rests on; answers add no new facts and promise no outcome.

Q1How is a natural emerald told apart from a synthetic or treated one?

Not by its green colour: microscopy is central, with multiphase fluid inclusions and characteristic mineral inclusions pointing to natural origin, and flux residues and roiled growth zoning revealing flux or hydrothermal synthesis.G&G Winter 2016Flattened gas bubbles with a flash effect mark clarity enhancement with oil or resin, and the chemistry is also probed with EDXRF in a professional gem laboratory.G&G Winter 2016According to the parent entry Beryl, a synthetic counterpart is commercially available.CIBJO Gemstone Book 2022 (via parent entry Beryl)Glass imitations exist: in one laboratory case a fractured green stone that looked like emerald was clarity-enhanced glass, with a single refractive index of 1.510 and gas bubbles instead of natural inclusions.G&G Spring 2020Whether one particular bead is natural, treated or synthetic — only a laboratory report can settle that.What this page can answer

Q2What gives emerald its green colour?

Emerald is beryl's green gem variety, coloured by traces of chromium and/or vanadium that substitute for aluminium in the crystal lattice.G&G Winter 2019Its colour runs from light to dark green, blue-green and yellow-green.GB/T 16553—2017Its pleochroism is moderate to strong, in blue-green and yellow-green.GB/T 16553—2017

Q3Are most emeralds oiled or filled, and does the filling last?

Yes: most emeralds are fracture-filled.GIA Gem Encyclopedia (care guide)Treatments with oil, resin, wax, plastic or dye are not permanent, so the stone should be kept away from all solvents, including dish-washing liquids, as well as chemicals and heat.CIBJO Gemstone Book 2022Light and chemicals can change the look of the oil, resin or polymer in fractures that reach the surface, or make it deteriorate.GIA Gem Encyclopedia (care guide)Laboratory reports remind readers that clarity enhancement can usually be removed or redone at any time, so a report reflects only the stone as examined.LMHC Information Sheet #5Oils and some resins can seep out of the fissures, especially under heat or pressure, or oxidise over time, so a trade association guide says sellers should be able to offer cleaning and re-treatment when needed.CIBJO Retailers' Reference Guide (2021) · LMHC Information Sheet #5

Q4Can you wear an emerald ring every day?

It is hard enough, but it needs more care than ruby or sapphire: emerald is 7.5–8 on the Mohs scale with fair to good toughness and commonly contains fractures, so the main risks are cracking from knocks and abrasion.GIA Gem Encyclopedia (care guide)Common sense says not to wear an emerald ring for gardening or other hard physical activity.CIBJO Retailers' Reference Guide (2021)Prong, bezel and channel settings call for caution, flush and pavé are best avoided, and heavily included stones or those with liquid inclusions need extra care in any setting.Gems & Gemology 1987 (Martin)Looked after, it lasts for generations.GIA Gem Encyclopedia (care guide)

Q5How should you clean an emerald, and can it get wet?

Warm soapy water with gentle scrubbing is safest; steam should be avoided because it can draw oil or unhardened resin out of fractures, and ultrasonic vibration can further weaken an already fractured stone.GIA Gem Encyclopedia (care guide)It should not be soaked in detergent, which may damage or remove fillers, and a soft cloth dampened with water is best.CIBJO Retailers' Reference Guide (2021)Solvents should also be avoided.Gems & Gemology 1987 (Martin)Heat can harm it, above all by extending existing fractures.GIA Gem Encyclopedia (care guide)

Q6What is the difference between emerald and green beryl?

The definition used on laboratory reports is a beryl whose green comes mainly from chromium or vanadium, at medium to strong saturation; iron-dominated green beryl with only traces of chromium does not count as emerald.LMHC Information Sheet #5According to the parent entry Beryl, beryl is a single mineral species, and emerald, aquamarine and others are its colour varieties rather than separate species.GIA Emerald Description (via parent entry Beryl)Whether emerald forms rather than common beryl depends directly on whether the chromophores are available.G&G Winter 2019

Q7Does a name like Colombian or Zambian emerald prove where it came from?

No: a locality name such as Colombia, Zambia, Brazil or Afghanistan is only a trade attribution, not a determined origin.G&G Winter 2019 · G&G Summer 1998Origin work is a laboratory exercise that compares inclusion suites and trace-element suites with reference databases for known localities.G&G Winter 2019 · G&G Summer 1998Because localities overlap and vary within a single deposit, the conclusion is probabilistic and may be only inconclusive.G&G Winter 2019 · G&G Summer 1998

Q8How do emeralds form?

Emerald forms when beryllium and chromium or vanadium meet through fluids; the classic model is beryllium-bearing pegmatites interacting with chromium-bearing ultramafic rocks.G&G Winter 2019Colombian emerald is different: it formed in an Early Cretaceous black shale-limestone sequence from basinal hydrothermal brines circulating along faults, with no evidence of magmatic activity.G&G Winter 2019No secondary emerald placers are known, since emerald is too brittle to withstand river transport and erosion.G&G Winter 2019Deposit ages span from the Archean, about 2.97 Ga at Gravelotte in South Africa, to the Cenozoic, about 9 Ma at Khaltaro in Pakistan.G&G Winter 2019

Q9What makes a good-quality emerald?

According to GIA, the most favoured emerald colours are bluish green to pure green, with vivid saturation and a tone that is not too dark.GIA Emerald Quality FactorsThe most prized emeralds are highly transparent, with colour spread evenly and no eye-visible colour zoning.GIA Emerald Quality FactorsEmeralds typically contain inclusions visible to the unaided eye, and the trade accepts them; they are often described as mossy or garden-like and are sometimes called 'jardin', French for garden.GIA Emerald Quality Factors

Q10What does emerald symbolize, and does it have healing powers?

There is no scientific evidence that emerald has healing powers: the UK advertising regulators ASA and CAP state that they have not seen evidence that crystal therapy can treat medical conditions.ASA/CAP guidance (UK)Its recorded cultural role is as the May birthstone: Jewelers of America and Japan's JJA list it for May, and the U.K. National Association of Jewellers lists it as traditional for May.Cultural recordsMuseum collections show early datable emerald settings in Greek and Roman jewellery, such as a Greek gold ring of about 330–300 BCE, and later in Byzantine work and 18th-century Indian gold.The Met 37.11.17 · The Met 21.29.2 +3

What this page can answer

This page covers

What we cannot conclude

  • Whether one particular bead is natural, treated or synthetic — only a laboratory report can settle that.
  • Geographic origin, unless an origin report accompanies the item.
  • Price, rarity or investment value: this wiki covers naming and disclosure only.

Material research: formation, causes and history

What authoritative sources say about how this material forms, what causes its colour and optical effects, where its name comes from and how people have used it. Each statement carries an evidence grade and its sources; it describes the material in general, not any specific piece.

How it forms

Emerald is beryl's green gem variety (Be3Al2Si6O18); its colour comes from traces of Cr and/or V that substitute for Al in the structure. Its formation requires an unusual meeting of elements: Be is very scarce in the upper continental crust, while Cr and V are concentrated in mantle/oceanic ultramafic rocks, and the two almost never coincide in ordinary settings. The classic model has Be-bearing pegmatites interacting with Cr-bearing ultramafic rocks (M-UMR), precipitating emerald in phlogopite/biotite reaction zones between quartz-tourmaline veins and metabasite. Colombian-style deposits show that not all emerald needs magmatism: in an Early Cretaceous black shale-limestone sequence, deep basinal brines rose along thrust faults and reacted with black shale, forming emerald without magmatic activity.

Scope: Covers the various deposit types of beryl emerald (Type I tectonic–magmatic, Type II tectonic–metamorphic); mineralisation styles vary by type and cannot be extrapolated from a single locality.

Sources G&G Winter 2019

Where it forms

Tectonic-magmatic type (Type I): Be-bearing pegmatites/hydrothermal veins intrude Cr-rich ultramafic rocks (e.g. Zambia, Brazil, Russia).

Sources G&G Winter 2019

Tectonic-metamorphic type (Type II): hydrothermal fluids circulate along shear/thrust zones in Be-Cr-bearing metasedimentary sequences (e.g. Colombian black shale).

Sources G&G Winter 2019

Shared prerequisite: Be (from Be-rich rocks) and Cr/V (from ultramafic rocks or black shale) must meet via fluid circulation.

Sources G&G Winter 2019

How it forms, step by step

  1. Be-rich rocks (pegmatite, black shale, etc.) supply beryllium.

    Sources G&G Winter 2019

  2. Fluid circulation (magmatic-hydrothermal or basinal brines) mobilises and transports Be, Cr and V.

    Sources G&G Winter 2019

  3. Water-rock reaction and metasomatism occur at lithological contacts or fault zones.

    Sources G&G Winter 2019

  4. Emerald precipitates in vugs of quartz-tourmaline veins or carbonate-silicate veins.

    Sources G&G Winter 2019

Link to appearance

Trace Cr/V substituting for Al colours beryl green, i.e. emerald; availability of the chromophore directly determines whether emerald forms rather than common beryl.

Sources G&G Winter 2019

Timescale

Deposit ages span from the Archean (Gravelotte, South Africa, ~2.97 Ga) to the Cenozoic (Khaltaro, Pakistan, ~9 Ma).

Sources G&G Winter 2019

Related base materials

  • Beryl: Mineral parent: emerald is the green gem variety of beryl coloured by Cr/V

Supporting findings

Emerald formation requires Be and Cr/V to meet via fluids; the classic model is Be-bearing pegmatites interacting with Cr-bearing ultramafic rocks.

Evidence grade A

Scope: The classic model does not cover the magmatic-free Colombian-type deposits.

Sources G&G Winter 2019

Colombian emerald occurs in an Early Cretaceous black shale-limestone sequence, formed by basinal hydrothermal brines circulating along faults with no evidence of magmatic activity.

Evidence grade A

Scope: This source model is specific to Type IIB deposits and cannot be extended to pegmatite-related localities.

Sources G&G Winter 2019

No secondary emerald placers are known, since emerald is too brittle to withstand river transport and erosion.

Evidence grade A

Scope: A boundary statement on emerald durability, contrasting with corundum placers.

Sources G&G Winter 2019

Type I (Zambian-style) emerald is mostly concentrated in phlogopite reaction zones between quartz-tourmaline veins and metabasite.

Evidence grade A

Scope: Reaction-zone width and hosting describe this deposit type only and are not generalisable.

Sources G&G Winter 2019

Recorded localities

Authoritative sources list the localities below; the list is not exhaustive.

Locality sketch mapLand outlines only; the map does not depict any national or regional boundary. Dots mark approximate positions. Base map: Natural Earth (public domain).

Africa

Asia

South America

These are localities recorded by authoritative sources, not an origin finding for any individual piece. The CIBJO Gemstone Book (2022, §4.2.3) says a place of origin names where a gem was mined or harvested, is a matter of opinion, does not imply a level of quality, and that cutting, processing or exporting centres must not be used to imply origin. See how far testing can go on this page, the origin determination guide and the overview of recorded localities.

Causes of colour and optical effects

Emerald is beryl's green gem variety; its colour arises from traces of chromium and/or vanadium that substitute for aluminium in the crystal lattice.

Evidence grade A

Scope: Colour mechanism applies only to beryl emerald, not to other green gems.

Sources G&G Winter 2019

Human use and museum objects

The collection evidence shows early datable emerald settings in Greek and Roman jewellery (Met 37.11.17, ca. 330-300 BCE; 1995.539.10a, b; 21.29.2, 1st-2nd century CE), later in Byzantine work (Cleveland 1947.178, 7th century) and 18th-century Indian Mughal/Jaipur gold (Cleveland 1966.515). The evidence pertains to the beryl parent material, not to this name uniquely.

Evidence grade A

Scope: Applies to collection jewellery recorded as emerald (the beryl variety) from Greece, Rome, Byzantium and India; the evidence pertains to the beryl parent material.

Sources The Met 37.11.17 · The Met 21.29.2 · The Met 95.16.13 +2

Objects recorded as emerald in these collections are mainly jewellery. Among the earlier are a Greek gold ring set with an emerald (Met 37.11.17, ca. 330-300 BCE) and Greek gold earrings with emeralds (Met 1995.539.10a, b, 2nd-1st century BCE), followed by Roman gold work of the 1st-2nd centuries CE (e.g. Met 21.29.2, a gold and emerald necklace; 95.16.13, gold/emerald/carnelian necklace; 20.239, a gold necklace with emerald beads). A Byzantine example is a 7th-century gold earring with emeralds (Cleveland 1947.178); a later one is an 18th-century Jaipur gold pendant with chain (Cleveland 1966.515). Emerald is the green, Cr/V-coloured gem variety of beryl; this record is not an independent material and the evidence above pertains to the beryl parent material. Design watercolours (e.g. the 53.626 group) and "emerald green" jadeite (acc. 02.18.733) are not emerald objects and are excluded.

Sources The Met 37.11.17 · The Met 1995.539.10a, b · The Met 21.29.2 +4

Scope: A museum object evidences only the existence and date of that artefact itself; it does not establish widespread ancient use of the material, nor does it attest the origin, naturalness, or treatment of any modern specimen.

Objects cited

500 BCE0500100015002000Met 37.11.17ca. 330–300 BCEMet 1995.539.10a, b2nd–1st century BCEMet 21.29.21st–2nd century CEMet 95.16.131st century CEMet 20.2393rd century CECMA 1947.178600sCMA 1966.5151700s
Dates of museum objectsDates from the museums' open-access records (CC0); each bar spans the whole period named in the record, with qualifiers such as “early” or “possibly” kept in the label rather than turned into a narrower range; an arrow marks a record that reads “before” or “after” a yearSource: The Met / Cleveland Museum of Art open-access records
  • The Met 37.11.17Gold ring set with an emerald · ca. 330–300 BCE · GreekGold, emerald
  • The Met 1995.539.10a, bPair of gold earrings with dolphins' heads with emerald, glass, and gold beads · 2nd–1st century BCE · GreekGold, emerald and banded glass
  • The Met 21.29.2Gold and emerald necklace · 1st–2nd century CE · RomanGold, emerald
  • The Met 95.16.13Gold, emerald, carnelian, banded onyx, and garnet necklace · 1st century CE · RomanGold, emerald, carnelian, banded onyx, with central cabochon garnet
  • The Met 20.239Gold necklace with emerald and variscite beads · 3rd century CE · RomanGold, emerald, and variscite
  • Cleveland Museum of Art 1947.178Earrings (pair) · 600s · Byzantium, early Byzantine periodgold, pearls, glass, and emeralds
  • Cleveland Museum of Art 1966.515Pendant with Chain · 1700s · Northwestern India, Rajasthan, Rajput Kingdom of JaipurGold, emerald, diamonds, enamel, and pearl

Cultural records for this material: Birthstone list.

How it is identified

Emerald cannot be certified natural, synthetic or treated from its green colour. Microscopy is central: multiphase fluid inclusions and characteristic mineral inclusions indicate natural origin, flux residues and roiled growth zoning reveal flux or hydrothermal synthesis, and flattened gas bubbles with a flash effect mark clarity enhancement with oil or resin. The chemistry of these stones is also probed with EDXRF. These methods demand a professional gem laboratory, and the conclusion should be issued by a qualified body.

Evidence grade A

Scope: Applies to the beryl group; separating natural, synthetic and treated material requires microscopic and chemical testing at a qualified gem laboratory, and is not a self-identification method.

Sources G&G Winter 2016

Emerald is often priced on locality, with goods traded under names such as Colombia, Zambia, Brazil or Afghanistan; emerald is also commonly clarity-treated. A locality name, however, is only a trade attribution and is not a determined origin. Origin work is a laboratory exercise: the deposit type is addressed first, then inclusion suites and trace-element suites (measured by methods such as laser ablation ICP-MS) are compared with reference databases for known localities to yield a conclusion of consistency or inconsistency with a source. Because the characteristic ranges of different localities overlap and vary within a single deposit, the conclusion is probabilistic and may be only inconclusive; heating, filling and diffusion alter the measurable features and must be excluded first. Origin cannot be inferred from appearance or name; an origin conclusion must be issued by a qualified laboratory for a specific specimen. This entry offers no self-test criteria or thresholds.

Evidence grade A

Scope: Origin cannot be inferred from appearance or name; an origin conclusion must be issued by a qualified laboratory for a specific specimen, and this entry provides no self-test criteria or thresholds.

Sources G&G Winter 2019 · G&G Summer 1998

In one laboratory case, a green step-cut stone that resembled emerald, complete with large fractures, proved to be clarity-enhanced manufactured glass: its single refractive index of 1.510 did not fit emerald's double refraction, and the microscope showed rounded gas bubbles in the body and flattened gas bubbles in the surface-reaching fractures instead of natural inclusions.

Evidence grade A

Scope: Describes identification features reported by a laboratory or educational source; it is not a test that a reader can rely on, and any single piece can only be identified by a gemmological laboratory.

Sources G&G Spring 2020

Other research findings

The GIA sources cited here record no size superlative for emerald. The beryl-group figures given by the 1988 article are a 2,594 ct aquamarine and a 2,054 ct green-gold beryl; neither is emerald.

Evidence grade A

Scope: States that the sources give no emerald record and that the beryl-group figures are an aquamarine and a green-gold beryl. Records change over time; limited to the source year (1988).

Sources G&G Spring 1988

The most favoured emerald colours are bluish green to pure green, with vivid saturation and a tone that is not too dark; the most prized emeralds are highly transparent, with colour spread evenly and no eye-visible colour zoning.

Evidence grade B

Scope: Quality factors as described by one educational source; not a grading standard and not a statement about the value of any piece.

Sources GIA Emerald Quality Factors

Emeralds typically contain inclusions visible to the unaided eye, and the trade accepts them; these inclusions are often described as mossy or garden-like and are sometimes called 'jardin', French for garden.

Evidence grade B

Scope: Quality factors as described by one educational source; not a grading standard and not a statement about the value of any piece.

Sources GIA Emerald Quality Factors

Oils and some resins used to fill emerald fissures can seep out, especially under heat or pressure, and others can oxidise over time, so a trade association guide says sellers should be able to offer cleaning and re-treatment of an emerald when needed. Laboratory report wording also anticipates residues of oils or resins left in fissures after 'cleaning' or through deterioration.

Evidence grade B

Scope: Describes what a trade association guide and a laboratory harmonisation body say about filled emeralds; it is not an instruction to have any stone re-treated, and whether a given emerald is filled, and with what, can only be established by laboratory testing.

Sources CIBJO Retailers' Reference Guide (2021) · LMHC Information Sheet #5

Limits of this research

  • Research status: Formation, occurrence or other material-specific findings found in authoritative sources
  • Emerald deposits are diverse; this record relies on a single GIA review synthesis and does not verify every locality detail.
  • The 'classic' and 'Colombian' models are parallel mechanisms and must not be applied interchangeably.
  • Synthetics and oiling treatments of emerald are outside the formation scope.

Methodology

Evidence grades

A
Standards bodies, government geological surveys, peer-reviewed research and museum records
B
Institutional educational material
C
Specialist databases or cautious readings

A statement is never graded above its strongest source.

This section is LumaLark's own factual restatement of public authoritative sources, credited item by item; it contains no verbatim excerpts, images or third-party logos.

DecideListing name, disclosure, care and treatments

Suggested listing name
Emerald

GB/T 16552—2017 Table A.1 “Emerald” · CIBJO Gemmological Laboratories Book 2024 §7.2.1.82 “Emerald”

Construction or treatment status

Natural; treatment common (require certificate to distinguish)

Treatments recorded for this material: Filled / Fracture-filled, Dyed, Coated

Related:Disclosure and cautions

This page cannot answer

Natural? · Origin · Price

A lab report settles these; this wiki covers naming and disclosure.

Related:What this page can answer

Answer at a glance

Emerald is often subjected to filling. Under GB/T 16552-2017, filling is graded by the material used, and must be stated in the name wherever it counts as a treatment (§5.4.1, Table 1). Do not assume it is unenhanced.

What this means for you

Before buying, check the recommended listing name "Emerald" and any disclosed treatments on this page, and ask the seller for a grading report if in doubt.

Known uncertainty

Last reviewed
2026-09-01

Care and wear

Normal care for every gemstone (CIBJO Gemstone Book §6.1), in brief:

  • Handle it gently.
  • Store pieces apart when not worn, so they cannot scratch each other.
  • Clean with warm soapy water and a soft brush.
  • Use ultrasonic cleaners only with caution.

The §6.1 wording and the full list of §6.2 special-care letters cited on this page are on the general gem care page.

Care

care (cleaning)4 sources compared

Emerald — care (cleaning): Do not soak it in detergent, for the same reason as with ultrasonic cleaning (fillers may be damaged or lost); a soft cloth dampened with water is best.

CIBJO Retailers' Reference Guide (2021)

Treatment state
any treatment state
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — care (cleaning): Warm soapy water with gentle scrubbing is safest; avoid steam, which can draw oil or unhardened resin out of fractures; most emeralds are fracture-filled, and ultrasonic vibration can further weaken a stone that is already fractured.

GIA Gem Encyclopedia (care guide)

Treatment state
any treatment state
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — care (cleaning): Some stones are susceptible to damage from ultrasonic cleaning. Do not expose them to ultrasonic cleaning.

CIBJO Gemstone Book 2022

CIBJO Gemstone Book §6.2:special-care code j

Treatment state
any treatment state
Source & check 2026-09-25
Source
Fact checked on
2026-09-25

Emerald — care (cleaning): ultrasonic and steamer: avoid; note: avoid solvents.

Gems & Gemology 1987 (Martin)

Treatment state
untreated
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — care (heat): Heat can harm it, above all by extending existing fractures.

GIA Gem Encyclopedia (care guide)

Treatment state
any treatment state
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — care (light): Light and chemicals can change the look of the oil, resin or polymer used to fill fractures that reach the surface, or make it deteriorate.

GIA Gem Encyclopedia (care guide)

Treatment state
treated
Only after these treatments
fissure filling with oil, fissure filling with resin
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — care (chemicals): Treatments with dye, oil, resin, wax or plastic are not permanent; keep it away from all solvents (including dish-washing liquids), chemicals and heat.

CIBJO Gemstone Book 2022

CIBJO Gemstone Book §6.2:special-care code k

Treatment state
treated
Source & check 2026-09-25
Source
Fact checked on
2026-09-25

Emerald — care (chemicals): Glass, plastic or hardened-resin fillers in cavities or fractures can be scratched more readily than the stone around them, or be more easily damaged by heat or some acids (e.g. hydrofluoric); keep it away from all chemicals, heat and abrasives.

CIBJO Gemstone Book 2022

CIBJO Gemstone Book §6.2:special-care code l

Treatment state
treated
Only after these treatments
fissure filling with resin
Source & check 2026-09-25
Source
Fact checked on
2026-09-25

care (wear)3 sources compared

Emerald — care (wear): Common sense says not to wear an emerald ring for gardening or other hard physical activity.

CIBJO Retailers' Reference Guide (2021)

Treatment state
any treatment state
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — care (wear): Mohs 7.5 to 8 with fair to good toughness, so it needs more care in wear than ruby or sapphire; looked after, it lasts for generations.

GIA Gem Encyclopedia (care guide)

Treatment state
any treatment state
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — care (wear): cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care.

CIBJO Gemstone Book 2022

CIBJO Gemstone Book §6.2:special-care code b

Treatment state
any treatment state
Source & check 2026-09-25
Source
Fact checked on
2026-09-25

Emerald — care (special care): dyed with colouring agents: special care (SC); avoid sudden temperature changes.

AGTA Gemstone Information Manual, 17th ed.

Treatment state
treated
Only after these treatments
dyeing
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — care (special care): colourless oil, wax or resin in fissures: special care (SC); avoid sudden temperature changes.

AGTA Gemstone Information Manual, 17th ed.

Treatment state
treated
Only after these treatments
fissure filling with oil, fissure filling with resin
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

care (setting)2 sources compared

Emerald — care (setting): Check pointed corners closely for durability; such stones are better in earrings, pins or pendants than in rings, to spare the points.

CIBJO Retailers' Reference Guide (2021)

Treatment state
any treatment state
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — care (setting): prong, bezel and channel: use caution; flush and pavé: avoid; note: heavily included stones or those with liquid inclusions need extra care in any setting.

Gems & Gemology 1987 (Martin)

Treatment state
untreated
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — care (repair): polishing: use caution; jeweller's torch, pickle pot and thermal shock: avoid; note: avoid heat, which may crack or break it; polishing compound can work into surface-reaching fractures.

Gems & Gemology 1987 (Martin)

Treatment state
untreated
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — care (display): heat in the display case, sunlight and artificial light: relatively safe.

Gems & Gemology 1987 (Martin)

Treatment state
untreated
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Each row's “Source & check” expands to the full source; the date beside it is the fact check date.

Common care questions and matching entries

CleaningCleaning Emerald: the CIBJO Blue Book (Official Gemstone Book) states that it must not be cleaned ultrasonically, in any treatment state; the GIA Gem Encyclopedia states that, in any treatment state, warm soapy water with gentle brushing is safest and steam should not be used; Martin's Gemstone Durability: Design to Display states that ultrasonic and steam cleaning should be avoided for untreated Emerald. Heat: the GIA Gem Encyclopedia states that, in any treatment state, heat can damage Emerald, in particular by extending existing fractures. Chemicals: the CIBJO Blue Book (Official Gemstone Book) states that treated Emerald should be kept away from all solvents (including all kinds of detergent), chemicals and high temperatures. Light: the GIA Gem Encyclopedia states that, for treated Emerald and specifically for fracture filling with oil or resin, light and chemicals can alter the appearance of, or age, the oil, resin or polymer used to fill surface-reaching fractures. Wear: the GIA Gem Encyclopedia states that, in any treatment state, at Mohs 7.5–8 it needs more care in wear than ruby or sapphire.

This table scrolls sideways on narrow screens.

QuestionMatching entries
Can it go in an ultrasonic or steam cleaner?Do not soak it in detergent, for the same reason as with ultrasonic cleaning (fillers may be damaged or lost); a soft cloth dampened with water is best; Warm soapy water with gentle scrubbing is safest; avoid steam, which can draw oil or unhardened resin out of fractures; most emeralds are fracture-filled, and ultrasonic vibration can further weaken a stone that is already fractured; care (cleaning); ultrasonic and steamer: avoid; note: avoid solvents
Heat and thermal shockHeat can harm it, above all by extending existing fractures; polishing: use caution; jeweller's torch, pickle pot and thermal shock: avoid; note: avoid heat, which may crack or break it; polishing compound can work into surface-reaching fractures
Light and displayLight and chemicals can change the look of the oil, resin or polymer used to fill fractures that reach the surface, or make it deteriorate; heat in the display case, sunlight and artificial light: relatively safe
Contact with acids, alkalis and household chemicalsTreatments with dye, oil, resin, wax or plastic are not permanent; keep it away from all solvents (including dish-washing liquids), chemicals and heat; Glass, plastic or hardened-resin fillers in cavities or fractures can be scratched more readily than the stone around them, or be more easily damaged by heat or some acids (e.g. hydrofluoric); keep it away from all chemicals, heat and abrasives
Wearing limits (knocks, settings)Common sense says not to wear an emerald ring for gardening or other hard physical activity; Mohs 7.5 to 8 with fair to good toughness, so it needs more care in wear than ruby or sapphire; looked after, it lasts for generations; cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care; Check pointed corners closely for durability; such stones are better in earrings, pins or pendants than in rings, to spare the points; prong, bezel and channel: use caution; flush and pavé: avoid; note: heavily included stones or those with liquid inclusions need extra care in any setting

Care entries by treatment state

The same entries grouped by the treatment state each applies to; each links to its full wording and source. Letters are CIBJO special-care codes, explained on the gemstone care page.

any treatment state

untreated

treated

treated (Only after these treatments: fissure filling with oil, fissure filling with resin)

treated (Only after these treatments: fissure filling with resin)

treated (Only after these treatments: dyeing)

Durability and wearing

Toughness

Fair to good

Sources GIA Gem Encyclopedia (care guide)

Treatments and identification leads

Registered treatmentsThe treatments recorded for Emerald are dyeing, filling and coating. Dyeing has the status colour treated; filling and coating have the status treated. Values not givenStability and prevalence for all three are marked with a dash, meaning the cited source gives no value, not none. Identification cluesAs identification leads, dyeing shows uneven colour distribution under magnification, with colour often concentrated in fractures or surface cavities, indistinct pleochroism and an anomalous UV-visible spectrum. What is seen with filling depends on the filler, with different features for colourless oil, wax or resin; infrared spectroscopy shows the filler's own characteristic absorption bands, and luminescence imaging shows how the filler is distributed. Coating can be detected under magnification by anomalous surface lustre and local peeling of the film; refractive index readings may be abnormal, and infrared and Raman spectroscopy can detect the characteristic peaks of the coating. The cited source is GB/T 16553—2017.

This table scrolls sideways on narrow screens.

TreatmentMarket frequency (CIBJO)Stability (CIBJO)GB/T 16552 categoryJJA/AGL listingIdentification leads
dyeingStatus: colour treated——Treatment—See identification leads
fillingStatus: treated——Graded — see §5.4.1, Table 1fillingSee identification leads
coatingStatus: treated——TreatmentcoatingSee identification leads
impregnation with a colourless agent———impregnation with a colourless agent—
impregnation with a coloured agent———impregnation with a coloured agent—

Where each treatment acts (schematics): Dyed · Filled / Fracture-filled · Coated

“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16553—2017; GB/T 16552—2017 Table B.1; JJA/AGL 2025

Whether a treatment has to show in the name differs between the two rule sets (this site’s paraphrase):

  • GB/T 16552—2017: a method classed as treatment has to be stated in the name itself — the method put before the name, or added in brackets after it; a method classed as optimization does not need to appear in the name, though one marked “Optimization (annotation required)” still has to be noted in the quality documents. Source: §5.4.2.1 a), b); §5.4.2.2 a)
  • CIBJO Gemstone Book 2022: no longer splits treatments into ones that need specific disclosure and ones that need only general disclosure: every treatment is to be disclosed, and the seller tells the buyer which treatment was used and what special care it calls for. Source: §4.2.5 Note 2, §4.2.5.1, pp.14–15

What this table covers

What this page can give

  • Registered treatments, their stability and how often they occur (see the table above)
  • Identification leads for each treatment, for use when sending a stone for testing

How lab reports word it

Further LMHC wording for this material (identification line, treatment wording, optional comments, durability note) is not itemised on this page; see LMHC information sheet #5 and the LMHC index on the laboratory testing page.

Emerald — how lab reports word it (definition used on reports): the definition used on reports: green mainly from chromium or vanadium, of medium to strong saturation; iron-dominated green beryl with only traces of chromium does not count.

LMHC Information Sheet #5

Definition in the information sheet (original wording): a beryl mainly coloured by chromium and or vanadium showing a medium to strong green saturation

Case
when the variety name may be used
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — how lab reports word it (treatment wording): The statement covers only the stone as examined; existing fissures could still be filled later.

LMHC Information Sheet #5

Wording on the report: At the time of examination, this gemstone does not show any clarity enhancement.

Case
no fissures or no filling
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — how lab reports word it (treatment wording): a reminder that clarity enhancement can usually be removed or redone at any time, so the report reflects only the stone as examined.

LMHC Information Sheet #5

Wording on the report: Clarity enhancement / modification is usually reversible and repeatable at any time.

Case
colourless to near-colourless filler in fissures
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — how lab reports word it (extent grades): Fissure filling is graded F1–F3 (minor, moderate, significant), and wide fractures or cavities are graded C1–C3; reports may give the code, the word or both.

LMHC Information Sheet #5

Wording on the report: F1 or minor

Case
colourless to near-colourless filler in fissures
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

VerifyNames, standards, technical facts, clauses and sources

Names

Standard and listing namesThe Chinese formal name for Emerald is given in GB/T 16552—2017 Table A.1, and the suggested listing name is Emerald. Names in four languagesNames are given in four languages: Simplified Chinese, Traditional Chinese, English (Emerald) and Japanese (a katakana transliteration); Japan's GSJ formal name is written in katakana with a kanji alternative, registered separately from the Japanese form among the four-language names. Trade and mineralogical namesThe mineralogical name is green beryl coloured by chromium or vanadium. Institution usageOn authority wording, GIA, the FTC and CIBJO record Emerald, the CIBJO wording coming from the CIBJO Gemmological Laboratories Book 2024; Gem-A is unchecked, and bodies without a recorded wording show the entry's own English name, which does not represent their position. Qualifier stripped from the title name: for GIA it corresponds to green beryl. National standard namesNational and regional formal names: Germany (RAL) writes Smaragd, the EU writes Emerald, India (BIS) writes Emerald/Panna, Thailand (GIT) writes Emerald/Mora-kot, and France (DGCCRF) writes Émeraude.

Authority wording

GIA, FTC, CIBJO, Gem-A
Emerald (on record for GIA, FTC, CIBJO (16 CFR Part 23 §23.25; CIBJO Gemmological Laboratories Book 2024 §7.2.1.82); Gem-A unchecked — bodies without a recorded wording show the entry's own English name)
GSJ (Japan) formal name
エメラルド／翠玉
Chinese formal name
祖母绿 (GB/T 16552—2017 Table A.1)
Mineralogical name
Green beryl colored by Cr/V

Four-language names

简体中文
祖母绿
繁體中文
祖母綠
English
Emerald
日本語
エメラルド

National and regional formal names

Germany (RAL)
Smaragd
European Union
Emerald
India (BIS)
Emerald / Panna (पन्ना)
Thailand (GIT)
Emerald / Mora-kot (มรกต)
France (DGCCRF)
Émeraude

Qualifiers stripped from the headline name

  • GIA: (green beryl)

See also: Misleading and prohibited trade names · Supplementary name index

Classification

Origin
Natural materials
Material domain
Natural inorganic gem materials
Browsing family
Beryl minerals and gem varieties
Identity tier
Mineral / gemstone variety
Mineral chemical class
Silicates
Construction or treatment status
Natural; treatment common (require certificate to distinguish)

Treatments listed by standards

GB/T Table B.1In the Emerald row of GB/T 16552—2017 Annex B, Table B.1, Emerald is listed with: filling, which improves or changes durability and appearance, its category defined by grade; dyeing, which improves or changes colour, in the treatment category; and coating, which improves or changes lustre, colour and other aspects of appearance, in the treatment category. The notes to Table B.1 and the graded definitions of the filling category are on the Gem treatments page. JJA/AGL designationsThe November 2025 revision of the Japanese JJA/AGL Definitions and Nomenclature of Gemstones and Ornamental Materials, in its list of main gemstone designations, places Emerald under the species beryl, with colour green (chromium); the treatments listed are impregnation with a colourless agent, impregnation with a coloured agent, coating and filling, corresponding respectively to filling, filling, coating and filling, plus an item for no sign of impregnation seen, which refers to filling. How to read the JJA/AGL table is explained on the Gem treatments page.

GB/T 16552-2017, Annex B, Table B.1

Table B.1, row “Emerald” (p.14):

This table scrolls sideways on narrow screens.

MethodEffectCategory
FillingImproves or changes durability and appearanceGraded — see §5.4.1, Table 1
DyeingImproves or changes colourTreatment
CoatingImproves or changes lustre, colour and other aspects of appearanceTreatment

What Table B.1 is, and how the “see 5.4.1” grades are defined: see the GB/T 16552: optimization vs treatment page.

JJA/AGL (Japan) table of principal gem names, 2025

This table scrolls sideways on narrow screens.

Gem nameSpeciesColourListed in the tableNotes
EmeraldBerylgreen (chromium)the source lists no untreated tier; no indication of impregnation (see Filled / Fracture-filled); impregnation with a colourless agent (Filled / Fracture-filled); impregnation with a coloured agent (Filled / Fracture-filled); coating (Coated); filling (Filled / Fracture-filled)

JJA/AGL definitions and nomenclature (2025 revision), table of principal gem names, p.16

How to read the JJA/AGL table: see the Gem treatments page.

What it is and how it's identified

Registered material facts for Emerald: chemical composition is Be3Al2Si6O18 with Cr, and Fe, Ti, V and other elements may also be present, the phase being beryl; the structure is crystalline, hexagonal, with a habit commonly of hexagonal prisms; Mohs hardness is 7.5–8 and cleavage is one imperfect direction; density is 2.67–2.9 g/cm³ (clause value 2.72, tolerance +0.18/−0.05, from which the range is derived); refractive index is 1.56–1.6 (clause value 1.577–1.583, tolerance ±0.017, from which the range is derived); birefringence is 0.005–0.009; optical character is anisotropic, uniaxial negative. Untreated Emerald shows moderate to strong pleochroism in bluish green and yellowish green, a body colour of light to dark green, bluish green and yellowish green, and a vitreous lustre; the UV-visible spectrum shows strong absorption peaks at 683nm and 680nm and weak peaks at 662nm and 646nm, with partial absorption at 580~630nm and absorption in the violet region.

Registered material facts

Each row carries its own source and check date and can be cited on its own; “—” means the cited source gives no value, not “none”.

Definition

Emerald — composition (chemistry): Be3Al2Si6O18 with Cr; Fe, Ti, V and other elements may also be present.

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald — composition (phase): beryl

CIBJO Gemmological Laboratories Book 2024

Source & check 2026-09-22
Source
Fact checked on
2026-09-22

Structure

Emerald — structure (overall): crystalline

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald — structure (crystal system): hexagonal

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald — structure (crystal habit): common hexagonal

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Durability

Emerald — Mohs hardness: 7.5–8

GB/T 16553—2017

123456789107.5–8References (diamond = value, bar = range; below)

Reference points on this site: Talc 1–3, Fluorite 4, Apatite 5–5.5, Orthoclase 6–6.5, Topaz 8, Diamond 10 (Source: GB/T 16553—2017); Gypsum 1.5–2, Calcite 3, Quartz 7 (Source: Handbook of Mineralogy); Corundum 9 (Source: GIA Gem Encyclopedia (care guide))

Mohs hardnessSource: GB/T 16553—2017
Does this standard apply
applies to this entry
General note
hardness only, not durability
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald — cleavage: imperfect in one direction

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Physical properties

Emerald — density: 2.67–2.9 g/cm³

GB/T 16553—2017

0.51.52.53.54.55.56.57.52.67–2.9
Specific gravitySource: GB/T 16553—2017
Does this standard apply
applies to this entry
Qualification

The clause we cite gives 2.72, with a stated tolerance of +0.18 / -0.05. The range shown here is worked out from that.

Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Optical

Optical effects on record: chatoyancyrepresentative example: cause in Tiger’s Eye (schematic)asterismrepresentative example: cause in Star Sapphire (schematic)

Emerald — optic character: uniaxial, optically negative (anisotropic)

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald — refractive index: 1.56–1.6

GB/T 16553—2017

1.31.72.12.52.93.31.56–1.6
Refractive indexSource: GB/T 16553—2017
Does this standard apply
applies to this entry
Qualification

The clause we cite gives 1.577–1.583, with a stated tolerance of ±0.017. The range shown here is worked out from that.

Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald — birefringence: 0.005–0.009

GB/T 16553—2017

00.050.10.150.20.250.30.005–0.009
BirefringenceSource: GB/T 16553—2017
Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald — pleochroism: blue-green and yellow-green, moderate to strong

GB/T 16553—2017

Treatment state
untreated
Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald — fluorescence (overall): generally none; sometimes long wave weak, orange-red, red; sometimes short wave weak, orange-red, red; fluorescence under short wave is usually weaker than under long wave.

GB/T 16553—2017

UV fluorescencesometimes: orange-redredweaksometimes: orange-redredweakDots are illustrative colours built from the colour names, not measured values

Treatment state
untreated
Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald — spectrum (UV-visible): 683 nm strong absorption peak; 680 nm strong absorption peak; 662 nm weak absorption peak; 646 nm weak absorption peak; 580~630 nm partial absorption band; absorption in the violet region.

GB/T 16553—2017

400450500550600650700 nm580–630646662680/683
Absorption spectrum (schematic)Line = absorption peak; hatching = absorption band; heavier or darker = higher recorded strength grade (not a measured intensity); Schematic: positions and strength grades as given by the cited source, not a measured curveSource: GB/T 16553—2017
Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald — spectrum (infrared): Diagnostic mid-IR bands arise from Si-O and similar groups in beryl; emerald that has been filled or clarity-enhanced departs from natural emerald in its functional-group-region bands.

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-22
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-22)
Fact checked on
2026-09-22

Emerald — optical effect (chatoyancy): seen

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald — optical effect (asterism): seen; rare

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald — magnification: gas-liquid inclusions, three-phase inclusions, mineral inclusions, growth striations, color band, grown crack.

GB/T 16553—2017

Treatment state
untreated
Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

body colour2 sources compared

Emerald — body colour: light to dark green, blue-green and yellow-green.

GB/T 16553—2017

Treatment state
untreated
Does this standard apply
applies to this entry
Qualification

The colours GB/T 16553—2017 lists for Synthetic Emerald overlap with this entry: green, blue-green and yellow-green.

General note
colour alone is not identity
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-26)
Fact checked on
2026-09-26

Emerald — body colour: green.

CIBJO Gemmological Laboratories Book 2024

Treatment state
untreated
Qualification

In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Aventurine Quartz, Diopside, Spodumene and other entries also name green or a greenish colour.

General note
colour alone is not identity
Source & check 2026-09-22
Source
Fact checked on
2026-09-22

How the sources relate

GB/T 16553—2017 and CIBJO Gemmological Laboratories Book 2024

complementary, no conflict

Both describe emerald as green; GB/T 16553—2017 adds the range from light to dark green as well as blue-green and yellow-green.

CIBJO definitions
chatoyancy, asterism

Quality factors

Emerald — quality factor (lustre): vitreous

GB/T 16553—2017

Treatment state
untreated
Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Each row's “Source & check” expands to the full source; the date beside it is the fact check date.

1.551.561.571.581.591.62.62.72.82.93Refractive indexSpecific gravity12345Emerald

This material (RI / SG midpoints): 1.58 / 2.79; Closest values: 1Qingtian Stone 1.565 / 2.77, 2Natural Conch Pearl / Natural Melo Pearl 1.595 / 2.84, 3Calcite 1.572 / 2.7, 4Brucite 1.57 / 2.89, 5Synthetic Emerald 1.565 / 2.69

Show the full chart (330 registered materials)1.41.51.61.71.81.922.12.22.32.41234567Refractive indexSpecific gravity12345Emerald

Outside the full chart's range, drawn as triangles at the edge (RI / SG midpoints): Hematite 3.045/5.12, Synthetic Rutile 2.76/4.26, Rutile 2.753/4.23, Synthetic Moissanite 2.67/3.22

Refractive index × specific gravity (all registered materials)Each dot is one material's registered refractive index and specific gravity (range midpoints, not measurements); gold = this material, dark = the nearest few (picked on this site by distance in RI ÷ 0.02 and SG ÷ 0.1, leaving out near-identical varieties of the same species)Source: each material's registered refractive index and specific gravity facts (GB/T 16553 and others; sources on each entry)

Testing and market

The identification leads for dyed Emerald are: under magnification the colour is unevenly distributed, often concentrated in fractures or surface pits; pleochroism is indistinct; and the UV-visible spectrum is abnormal. For filled Emerald, the leads depend on the filler: colourless oil can be seen under magnification in surface-reaching fractures, fluoresces yellowish green or greenish yellow under long-wave UV, and may sweat out on contact with a thermal needle; resin fillers show a lustre different from the host where exposed at the surface, with flashes and gas bubbles visible; the infrared spectrum can detect characteristic bands of the filler, and luminescence imaging can show the filler's distribution. For coated Emerald, magnification shows abnormal surface lustre and local peeling of the film, refractive index readings may be abnormal, and infrared and Raman spectra can detect characteristic peaks of the coating. The GB/T 16553—2017 identification leads for dyeing, filling and coating can only be used as a reference for Emerald and do not govern it directly. The CIBJO laboratory protocol requires particular checks for clarity enhancement (including filling of cavities and wide fractures), synthetics, coating and dyeing; Fourier-transform infrared spectroscopy distinguishes synthetic from natural and identifies fillers, while Raman spectroscopy only identifies fillers.

The tests the CIBJO laboratory protocol requires for this material, and what each method means, are in the protocol table on the laboratory testing page: §6.1.30.

How far testing can go

Emerald that has undergone dyeing can be identified by the following features: Under magnification the colour is unevenly distributed and mostly concentrated between fissures or in surface hollows; there is no obvious pleochroism; the UV-visible spectrum looks abnormal.

GB/T 16553—2017

Treatment state
colour treated
Does this standard apply
can be followed as a reference only
Treatment
dyeing
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (dyeing) (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald that has undergone filling can be identified by the following features: What is seen depends on the filler. Colorless oil: magnification finds it in fissures reaching the surface; the oil is mostly colorless to pale yellow, may glow yellow-green or green-yellow under long-wave ultraviolet light, and may exude when touched with a hot point.

Wax: it may exude when touched with a hot point. Resin: magnification shows that the exposed part of the filler differs in surface lustre from the host gem, with flash and bubbles visible where the filling sits. Beyond that, infrared spectroscopy reveals the characteristic infrared absorption bands of the filler, and luminescence imaging (an ultraviolet fluorescence viewer, for instance) shows how the filler is distributed.

GB/T 16553—2017

Treatment state
treated
Does this standard apply
can be followed as a reference only
Treatment
filling
Source & check 2026-09-22
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (filling) (locator checked 2026-09-22)
Fact checked on
2026-09-22

Emerald that has undergone coating can be identified by the following features: Under magnification the surface luster is abnormal and the film can be seen peeling off in places; refractive index readings may be abnormal, and infrared and Raman spectra show characteristic peaks of the film.

GB/T 16553—2017

Treatment state
treated
Does this standard apply
can be followed as a reference only
Treatment
coating
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.7 (coating) (locator checked 2026-09-21)
Fact checked on
2026-09-21

Emerald — criteria for distinction from other varieties: green colour due to chromium and vanadium.

CIBJO Gemmological Laboratories Book 2024

Treatment state
untreated
Source & check 2026-09-22
Source
Fact checked on
2026-09-22

Emerald — what the CIBJO laboratory protocol says to watch for: clarity enhancement (also cavity and wide fracture filling), synthetics, coating and dye.

CIBJO Gemmological Laboratories Book 2024

Treatment state
any treatment state
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Emerald — notes on test methods in the CIBJO laboratory protocol:

CIBJO laboratory protocol, in its own order; only the notes registered on this site
Test methodWhat the protocol notes for it
Phenomena: Star, Cat’s-eye, trapiche;
UV-Visible(-NIR) spectroscopy: Origin;
FTIR(-NIR) spectroscopy: Synthetic/natural and filler ID;
EDXRF chemistry: Origin;
Raman spectroscopy: Only for filler ID;
LA-ICP-MS Chemistry: If necessary for origin

CIBJO Gemmological Laboratories Book 2024

Treatment state
any treatment state
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Each row's “Source & check” expands to the full source; the date beside it is the fact check date.

Clause-level definitions

Emerald has a direct definition in the CIBJO Gemmological Laboratories Book 2024 under the term Emerald, defined as the green variety of beryl, that is, green beryl. The cross-check for Emerald shows it is defined directly by CIBJO and also appears in the GB/T annex; GB/T 16552—2017 Annex A, Table A.1 also lists this material under the name Emerald.

This table scrolls sideways on narrow screens.

TermClauseDefinitionCross-check
Emerald7.2.1.82green variety of berylDefined directly by CIBJO; also present in the GB/T annex.

Evidence and sources

Authority basis and clause sources

GB/T 16552—2017
Listed Table A.1 “Emerald” · Source
CIBJO Gemmological Laboratories Book 2024
Listed §7.2.1.82 “Emerald” · Source

Sources

Further reading

Related pages

Treatments recorded for this material

Recorded cultural contexts

Birthstone list

The U.S. Jewelers of America roster lists Emerald for May; the U.K. National Association of Jewellers chart lists Emerald as traditional for May; and Japan's JJA 2021 revised roster lists Emerald for May. This records trade-association convention only; it does not establish material identity, natural origin, treatment, provenance, or effect.

Relation
Industry list inclusion

This table scrolls sideways on narrow screens.

Publisher or holderRegionFrom / periodSource and locator
Jewelers of AmericaUnited States1912 to the presentJewelers of America, “Birthstone Jewelry” (web page, consulted 2026-08-22)
Birthstone roster table, May row: Emerald
Japan Jewellery AssociationJapanfrom 20 December 2021Tanjoseki (Japanese birthstone roster, Japan Jewellery Association page; revision of 20 December 2021)
2021 revised birthstone roster, May row: Emerald
National Association of JewellersUnited Kingdom—National Association of Jewellers, “Zodiac Birthstones Jewellery: Star Signs, Gemstones and Their Meaning” (web page, consulted 2026-08-22)
Zodiac birthstone chart, May row: Emerald (Traditional)

Related entries and topic cluster

Parent entry and related pages on this site. Rows marked “Planned” are suggested new content and have no link yet.

Related-entry tree for Beryl on this site: 11 entries listed by this site's parent-entry links; synthetic, treated and similar entries carry their recorded state after the name; this page (Emerald) is marked.

This table scrolls sideways on narrow screens.

PageContentStatus
Browsing familyBeryl minerals and gem varietiesLive
Treatments recorded for this materialFilled / Fracture-filled, Dyed, CoatedLive
Related articlesTo be added (placeholder)Planned

Who maintains this page

The material facts in the Emerald entry are maintained by the LumaLark wiki and matched one by one to the standard clauses or institutional sources they cite: every fact carries its source (with a clause or page locator) and a check date, so it can be traced back to the original; clause-level definitions also carry a cross-check result. The entry exists so that buyers and sellers can check naming, disclosure and material facts item by item.

Facts editor
Ralph
Reviewer
June
How facts are checked
Each fact is matched to the clause it cites; facts checked between 2026-09-21 and 2026-09-26
Last revised
2026-10-12
Purpose
Lets buyers and sellers check naming, disclosure and material facts clause by clause.

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