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Amethyst

A purple variety of Quartz; its basic name listed in GB/T 16552-2017 Appendix A Table A.1 is Amethyst, written in a shorter Chinese form. 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 2026-10-13Who maintains this page

FAQCare and wear

Questions people ask about Amethyst

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

Q1Is amethyst heat-treated?

Amethyst can be heat-treated, and the treatment is hard to detect: dark amethyst may lighten on heating, and heated quartz gems are stable in colour.GB/T 16553—2017Pale amethyst and even pale quartz have also been dyed purple, while fracture filling is rare.GIA Amethyst Quality FactorsHeating to lighten the colour or remove smoky tones is listed as a treatment that calls for special care.AGTA Gemstone Information Manual, 17th ed.Filling fissures with oil is reported as occasional in the trade.CIBJO Gemstone Book 2022Filling fissures with resin is reported as rare.CIBJO Gemstone Book 2022

Q2How can you tell real amethyst from glass or synthetic amethyst?

Not by its purple colour: for iron-bearing quartz such as ametrine, natural and synthetic material are separated by combining a check of twinning and colour zoning with EDXRF chemical analysis and infrared spectra.G&G Summer 2014Synthetic counterparts of amethyst are common in the trade.CIBJO Gemstone Book 2022Glass is also used to imitate amethyst, though it is less brilliant.GIA Introduction to Imitation GemsAmethyst commonly shows Brazil-law twinning.GB/T 16553—2017Whether one particular bead is natural, treated or synthetic — only a laboratory report can settle that.What this page can answer

Q3Is citrine just heated amethyst?

Some can be: amethyst may turn into citrine or green quartz when heated.GB/T 16553—2017Strong heat can bleach amethyst colourless or turn it into citrine and back, so jeweller's torch work on it is to be avoided.Gems & Gemology 1987 (Martin)Whether one particular bead is natural, treated or synthetic — only a laboratory report can settle that.What this page can answer

Q4Why is amethyst purple?

Its purple is linked to trivalent iron (Fe3+) in the quartz lattice, and the iron-bearing crystal turns purple only after exposure to natural background radiation.G&G Fall 2024 · American Mineralogist (Cohen, 1985) +1Its body colour runs from violet to purple to reddish purple.CIBJO Gemmological Laboratories Book 2024It typically shows colour zoning in angular bands running from darker to lighter.GIA Amethyst Description

Q5Does amethyst fade in the sun?

It can: amethyst may fade or revert to its original colour in strong light, so it should not be worn or left in strong light for long periods.CIBJO Gemstone Book 2022Ordinary display light is rated relatively safe, but long exposure to strong light and heat may fade it.Gems & Gemology 1987 (Martin)Some unheated material may fade in long sunlight as well.AGTA Gemstone Information Manual, 17th ed.

Q6How do amethyst geodes form?

Geode cavities in basalt can begin as gas bubbles in cooling lava that leave small rounded cavities, later filled by minerals deposited from solutions circulating through the rock.USGS Bulletin (Isle Royale)In basalt-hosted geodes, silica- and iron-bearing hydrothermal fluids precipitate amethyst in these cavities.G&G Fall 2024Amethyst always forms at relatively low temperature (≤400°C) and shallow depth.G&G Fall 2024

Q7How do you clean amethyst safely?

Warm soapy water is safe; ultrasonic cleaning is usually fine except for the rare dyed or fracture-filled stone, and steam cleaning is not advised.GIA Gem Encyclopedia (care guide)Another source is stricter and advises against ultrasonic cleaning altogether.CIBJO Gemstone Book 2022Sudden temperature changes can crack it, and it should not be heated.GIA Gem Encyclopedia (care guide)Hydrofluoric acid, ammonium fluoride and alkaline solutions can damage it.GIA Gem Encyclopedia (care guide)

Q8Is amethyst durable enough for daily wear?

Yes: amethyst is Mohs 7 with good toughness and suits any jewellery, including rings, though everyday dust is mostly quartz, so it needs guarding against scratches.GIA Gem Encyclopedia (care guide)Avoid knocking it, or small fissures may form, especially where facets meet.CIBJO Retailers' Reference Guide (2021)

Q9What does amethyst symbolize, and does it have healing powers?

There is no scientific evidence that amethyst 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)It is the February birthstone on the lists of Jewelers of America and Japan's JJA, and a traditional February stone for the U.K. National Association of Jewellers.Cultural recordsMuseum objects show amethyst used for beads as early as Egypt's Middle Kingdom, around the 20th–19th centuries BCE.The Met 15.3.544 · The Met 10.130.2895 +4

Q10What makes good-quality amethyst?

The finest amethyst is a strong reddish purple or purple with no visible colour zoning; brownish or bronze tints, or noticeable zoning, lower its value dramatically.GIA Amethyst Quality Factors

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

  • Amethyst cross-section (schematic)
  • Darker band
  • Lighter band
How amethyst forms: a schematic animation, not to scale; the captions are taken from the research record under “Material research” on this page.

If you reuse this animation, please credit LumaLark Wiki and link to this pageLicense: CC BY 4.0

Scene-by-scene transcript (10 scenes, with evidence grades and sources)

The caption of each scene in the animation above, with its evidence grade and sources.

  1. Scene 1What amethyst is

    Amethyst is the purple variety of quartz (SiO₂)

    Scope: Covers the geological and gemmological formation of the natural purple variety of quartz

    Sources
  2. Scene 2A geode’s cavity can begin as a vesicle in lava

    Cavities such as those of basalt geodes can begin as vesicles in lava: as a lava flow cools, bubbles of gas or steam expand while the rock solidifies, leaving small rounded cavities called vesicles

    Scope: The general origin of vesicles and amygdules (the source describes lavas of Isle Royale, Lake Superior, where all vesicles have since been filled and converted to amygdules)

    Scope: For the geode cavities of the Paraná Volcanic Province, the source of the Cordillera Flow entry explains the cavities as formed by hot-water alteration.

    Evidence grade A
    Sources
  3. Scene 3Amethyst always forms at relatively low temperature and shallow depth

    Whatever the geological setting, crystallization always takes place at shallow crustal depth and relatively low temperature (≤400°C).

    Scope: General rule; deposit-specific temperatures/depths follow local studies.

    Evidence grade A
    Sources
  4. Scene 4Basalt geodes: fluids precipitate in the vesicle

    Basalt-hosted geodes: silica- and iron-bearing hydrothermal fluids precipitate amethyst in vesicles/geodes within basalt.

    when minerals deposited from solutions circulating through the rock later fill them, the fillings are called amygdules.

    Evidence grade A
    Sources
  5. Scene 5Fe³⁺ enters the growing quartz

    Under oxidizing conditions, dissolved trivalent iron (Fe³⁺) from silica-bearing fluids is incorporated into the growing quartz lattice.

    Sources
  6. Scene 6Purple appears only after natural radiation

    The Fe³⁺-bearing crystal is then exposed to natural background radiation, and only then does the purple colour appear.

    Scope: Natural amethyst only

    Scope: The exact state of the iron after irradiation (e.g. whether Fe⁴⁺ forms) is debated in the literature; this statement does not cover the microscopic mechanism.

    Evidence grade A
    Sources
  7. Scene 7Example: at La Manche, amethyst forms in the last stage

    At La Manche: calcite-galena crystallize first, barite follows, and amethyst grows on barite in open cavities within calcite as the last hydrothermal stage.

    Scope: Based on the single La Manche deposit; not a universal paragenetic sequence.

    Evidence grade A
    Sources
  8. Scene 8Example: a low crystallization temperature at La Manche

    La Manche amethyst formed at low temperature: primary fluid inclusions homogenized at 66.2–98.0°C (average 75.5°C), and from this and the shallow geological setting the authors infer a formation temperature likely below 100°C, markedly lower than the 240–370°C of sulfide-bearing veins in the region.

    Scope: Homogenization temperatures are only minimum trapping temperatures; "likely <100°C" is the authors' inferred upper bound, not a measured range. Applies to La Manche and regional comparison.

    Evidence grade A
    Sources
  9. Scene 9Example: the reduced lower tier of the Cordillera Flow

    world-class amethyst-geode and agate-geode deposits occur in the reduced lower tier; according to the source, reducing and acidic hot water formed these amethyst and agate deposits.

    Scope: This is the source's interpretation for the Cordillera Flow only; how it squares with this record's general statement that forming Fe³⁺ requires oxidizing conditions (from the La Manche paper) is not discussed by either source.

    Sources
  10. Scene 10Common angular colour zoning

    Amethyst, the purple variety of the mineral species quartz, typically displays colour zoning made up of angular bands that run from darker to lighter.

    Timescale: No absolute age or growth duration is given

    Sources

In brief: Amethyst is the purple variety of quartz (SiO₂), and its colour is linked to interstitial trivalent iron (Fe³⁺) in the crystal lattice: forming Fe³⁺ requires oxidizing conditions, and the iron-bearing crystal must later be exposed to natural background radiation before the purple colour appears.

Full research record (formation summary, where it forms, 5 formation steps, link to appearance, timescale, related base materials, 3 supporting findings)

Amethyst is the purple variety of quartz (SiO₂), and its colour is linked to interstitial trivalent iron (Fe³⁺) in the crystal lattice: forming Fe³⁺ requires oxidizing conditions, and the iron-bearing crystal must later be exposed to natural background radiation before the purple colour appears. Whatever the geological setting, crystallization always takes place at shallow crustal depth and relatively low temperature (≤400°C). Commercially important deposits occur mainly as geodes in basalt or as epigenetic hydrothermal veins (formed later than the host rock). At the La Manche deposit in Newfoundland, Canada, amethyst is the final hydrothermal stage of a calcite-galena-barite-quartz vein, growing on barite in open cavities within layered calcite at an inferred temperature likely below 100°C and moderate salinity (~10.7 eq. wt.% NaCl), with individual pockets inferred to have behaved as relatively closed systems.

Scope: Covers the geological and gemmological formation of the natural purple variety of quartz; does not address the origin of synthetic amethyst or of material colour-altered by artificial irradiation or heat treatment.

Sources G&G Fall 2024 · GIA Amethyst Description
Where it forms

Epigenetic hydrothermal veins: mineralizing fluids travel along faults, joints or breccias; most such vein deposits are nearly monomineralic, and La Manche, where amethyst occurs with base-metal sulfides such as galena, is one of the few examples of that association.

Sources G&G Fall 2024

Miarolitic pegmatite cavities and skarns: amethyst may also crystallize in late, relatively low-temperature hydrothermal stages of magmatic systems.

Sources G&G Fall 2024

Example: in the Cordillera Flow along the Brazil–Uruguay border in the southern Paraná Volcanic Province (deposits in Artigas, Uruguay; those on the Brazilian side remain concealed), world-class amethyst-geode and agate-geode deposits occur in the reduced lower tier; according to the source, reducing and acidic hot water formed these amethyst and agate deposits.

Sources Brazilian Journal of Geology
How it forms, step by step

  1. Under oxidizing conditions, dissolved trivalent iron (Fe³⁺) from silica-bearing fluids is incorporated into the growing quartz lattice.

    Sources G&G Fall 2024

  2. Silica- and iron-bearing fluids precipitate quartz in open cavities of geodes or veins at relatively low temperature (≤400°C) and shallow depth; amethyst typically occurs in the latest stage of quartz growth.

    Sources G&G Fall 2024

  3. At La Manche the outermost layer of the crystals is typically colourless; the authors hypothesize that changing conditions precipitated the dissolved iron as iron-rich minerals (hematite, goethite, sulfides), leaving no iron in the fluid during the final growth stage.

    Sources G&G Fall 2024

  4. The Fe³⁺-bearing crystal is then exposed to natural background radiation, and only then does the purple colour appear.

    Sources G&G Fall 2024

  5. At La Manche: calcite-galena crystallize first, barite follows, and amethyst grows on barite in open cavities within calcite as the last hydrothermal stage.

    Sources G&G Fall 2024
Link to appearance

A crystal with interstitial Fe³⁺ impurities in its lattice turns purple only after exposure to natural radiation; amethyst commonly shows angular colour zoning from darker to lighter (at La Manche the outermost layer is typically colourless).

Sources GIA Amethyst Description · G&G Fall 2024
Timescale

The sources give fluid-inclusion homogenization temperatures and fluid salinity (crystallization at La Manche likely below 100°C) but no absolute age or duration for amethyst itself; the quoted ~620-605 Ma constrains the age of the host rocks, and the Devonian Acadian orogeny (during or after which the veins formed) constrains the time of vein formation; neither is an amethyst growth time.

Sources G&G Fall 2024
Related base materials
  • Quartz (SiO₂): variety-of | Amethyst is the purple variety of quartz
Supporting findings

Amethyst always forms at relatively low temperature (≤400°C) and shallow crustal depth; commercially important deposits are basalt-hosted geodes and epigenetic hydrothermal veins.

Evidence grade A

Scope: General rule; deposit-specific temperatures/depths follow local studies.

Sources G&G Fall 2024

At La Manche, amethyst is the final hydrothermal stage of the calcite-galena-barite-quartz vein, growing on barite inside open cavities within layered calcite.

Evidence grade A

Scope: Based on the single La Manche deposit; not a universal paragenetic sequence.

Sources G&G Fall 2024

Cavities such as those of basalt geodes can begin as vesicles in lava: as a lava flow cools, bubbles of gas or steam expand while the rock solidifies, leaving small rounded cavities called vesicles; when minerals deposited from solutions circulating through the rock later fill them, the fillings are called amygdules.

Evidence grade A

Scope: The general origin of vesicles and amygdules (the source describes lavas of Isle Royale, Lake Superior, where all vesicles have since been filled and converted to amygdules); the specific conditions under which amethyst precipitates in basalt geodes are covered by other entries in this record. For the geode cavities of the Paraná Volcanic Province, the source of the Cordillera Flow entry explains the cavities as formed by hot-water alteration.

Sources USGS Bulletin (Isle Royale)

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

Europe

North America

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

Amethyst's purple colour is linked to interstitial trivalent iron (Fe³⁺) in the quartz lattice: forming Fe³⁺ requires oxidizing conditions, and the iron-bearing crystal must later be exposed to natural background radiation before the purple colour appears.

Evidence grade A

Scope: Natural amethyst only; synthetic or artificially treated/irradiated material is out of scope. The exact state of the iron after irradiation (e.g. whether Fe⁴⁺ forms) is debated in the literature; this statement does not cover the microscopic mechanism.

Sources G&G Fall 2024 · American Mineralogist (Cohen, 1985) · Phys. Chem. Minerals (Czaja et al., 2017)

Human use and museum objects

Objects in The Met and the Cleveland Museum of Art show that the earliest datable use of amethyst as beadwork occurs in Egypt's Middle Kingdom around the 20th-19th centuries BCE (e.g. Met 15.3.544, 10.130.2895), and that it continued to be used as beads into the Sasanian and Byzantine periods (e.g. Met 34.107.109, 17.190.1652).

Evidence grade A

Scope: Applies to collection objects recorded as amethyst (purple quartz variety) from Egypt, Sasanian Iran and Byzantium; other quartz varieties are not covered.

Sources The Met 15.3.544 · The Met 10.130.2895 · The Met 26.7.738 +3

The Metropolitan Museum of Art holds amethyst beadwork whose dates reach back to Egypt's Middle Kingdom in the early 2nd millennium BCE: a string of beads (acc. 15.3.544, ca. 1981-1295 B.C., Memphite Region) and a ball bead (acc. 10.130.2895, ca. 1981-1550 B.C.); a Dynasty 18 ball bead bearing the name of Hatshepsut (acc. 26.7.738, ca. 1479-1458 BCE) follows. The Cleveland Museum of Art's Middle Kingdom string of beads (acc. 1914.750, 2040-1648 BCE) pairs amethyst with gold. Later Sasanian (Met 34.107.109, ca. 3rd-7th century CE, Iran) and Byzantine (Met 17.190.1652, 6th-7th century) pieces show continued use as beadwork across West Asia and the Mediterranean. Amethyst is the purple variety of quartz; the above collection evidence pertains to that parent material (quartz, amethyst variety).

Sources The Met 15.3.544 · The Met 10.130.2895 · The Met 26.7.738 +3

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

3000 BCE2000 BCE1000 BCE01000CMA 1914.7502040–1648 BCEMet 15.3.544ca. 1981–1295 B.C.Met 10.130.2895ca. 1981–1550 B.C.Met 26.7.738ca. 1479–1458 BCEMet 34.107.109ca. 3rd–7th century CEMet 17.190.16526th–7th century
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 15.3.544String of beads · ca. 1981–1295 B.C. · Memphite RegionAmethyst
  • The Met 10.130.2895Ball bead · ca. 1981–1550 B.C. · EgyptAmethyst
  • The Met 26.7.738Ball Bead with Name of Hatshepsut · ca. 1479–1458 BCE · EgyptAmethyst
  • Cleveland Museum of Art 1914.750String of Beads · 2040–1648 BCE · Egypt, Middle Kingdom (2040–1648 BCE)amethyst and gold
  • The Met 34.107.109Bead · ca. 3rd–7th century CE · Sasanian · IranAmethyst
  • The Met 17.190.1652Gold Necklace with Amethysts, Glass, and Gold Beads · 6th–7th century · ByzantineGold, amethyst, (colored glass or rock crystal and emerald) beads

Cultural records for this material: Birthstone list.

How it is identified

Amethyst is not judged by its purple colour and outward look: for iron-bearing quartz such as ametrine, natural and synthetic material can be separated by combining a visual check of twinning and colour zoning with chemical analysis (EDXRF) and infrared spectra, because the colour boundary's orientation relative to the optic axis differs between the two. Recognising this calls for a trained gemmologist and instruments, and the verdict should come from a qualified gem laboratory; no reader should attempt such a determination unaided.

Evidence grade A

Scope: Limited to separating natural from synthetic iron-bearing purple/yellow quartz (e.g. ametrine); the reading relies on instruments and expertise, must be confirmed by a qualified gem laboratory, and is not a self-identification method.

Sources G&G Summer 2014

Glass is one of the materials used to imitate amethyst: it can be made in virtually any colour, though it is less brilliant than the stone it imitates.

Evidence grade B

Scope: The source names glass as an amethyst imitation but gives no features for telling them apart; separating them needs testing.

Sources GIA Introduction to Imitation Gems

Other research findings

Amethyst, the purple variety of the mineral species quartz, typically displays colour zoning made up of angular bands that run from darker to lighter.

Evidence grade A

Scope: Defines the natural purple quartz variety; other purple gems (sapphire, tanzanite) excluded.

Sources GIA Amethyst Description

The GIA sources used here give no size record for amethyst. The quartz-family records listed in the 1988 article are a faceted quartz egg (7,000 ct) and a smoky quartz whose weight is incomplete in the text extraction of the original table (the leading digit is missing), so that figure is not cited here. Neither is amethyst.

Evidence grade A

Scope: States that the sources give no amethyst record, and distinguishes the quartz-family records. The original table's text extraction is incomplete, so the defective figure is not quoted. Records are superseded over time; the statement is bounded to the source year (1988).

Sources G&G Spring 1988

The finest amethyst colour is a strong reddish purple or purple without visible colour zoning; brownish or bronze tints in the purple, or noticeable zoning, lower its value dramatically.

Evidence grade B

Scope: Colour as a quality factor according to one educational source; not a grading standard and not a statement about the value of any piece.

Sources GIA Amethyst Quality Factors

Heating can lighten very dark amethyst; pale, lower-quality amethyst and even pale quartz have been dyed purple, and fracture filling of surface-reaching fractures to improve apparent clarity is rare.

Evidence grade B

Scope: Treatments named by one educational source; it gives no market frequency for heating, and whether a particular stone is treated needs laboratory testing.

Sources GIA Amethyst Quality Factors

Limits of this research

  • Research status: Formation, occurrence or other material-specific findings found in authoritative sources
  • Occurrence and temperature data center on the single La Manche deposit; the only source dedicated to a basalt-geode deposit is the Cordillera Flow study in the Paraná Volcanic Province (the La Manche paper also compares literature on Brazilian and Uruguayan basalt geodes), and vesicle origin comes from a general account based on Isle Royale lavas; not all amethyst deposit types are covered.
  • No absolute age or growth duration is given; only fluid-inclusion homogenization temperatures (minimum trapping temperatures) were measured, and <100°C is an upper bound inferred from them.
  • The formation temperature of geode-hosted amethyst in Brazilian basalt is not settled: one study suggests below 100°C, while primary fluid-inclusion estimates give 152–238°C; the authors note, however, that most inclusions in such amethyst are monophase and the two-phase inclusions measured may have leaked, giving unreliable results, as low oxygen-isotope temperatures also suggest.

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
Amethyst

GB/T 16552—2017 Table A.1 “Amethyst”, 5.1.1 a) · CIBJO Gemmological Laboratories Book 2024 §7.2.1.10 “Amethyst”, §7.2.1.190 “Quartz”

Construction or treatment status

Natural; common industry optimization (verify with certificate)

Treatments recorded for this material: Heated / Heat-treated, Irradiated (via parent material), Filled / Fracture-filled (via parent material), Dyed (via parent material), Coated (via parent material)

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

The Chinese standard lists Amethyst under a different Chinese name from its common trade name (GB/T 16552—2017 Table A.1); use "Amethyst" for listings.

Evidence

  • GB/T · Table A.1, row 紫晶 (Amethyst (GB/T formal))

What this means for you

Before buying, check the recommended listing name "Amethyst" 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)3 sources compared

Amethyst — 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
treated
Only after these treatments
fissure filling with oil, fissure filling with resin
Source & check 2026-09-25
Source
Fact checked on
2026-09-25

Amethyst — care (cleaning): ultrasonic and steamer: use caution; note: avoid thermal shock.

Gems & Gemology 1987 (Martin)

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

Amethyst — care (cleaning): Warm soapy water is safe; ultrasonic cleaning is usually fine except for the rare dyed or fracture-filled stone; steam cleaning is not advised.

GIA Gem Encyclopedia (care guide)

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

Amethyst — care (heat): Sudden temperature changes can crack it, and it should not be heated.

GIA Gem Encyclopedia (care guide)

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

Amethyst — care (light): may fade or revert to its original colour in strong light; do not wear or leave it in strong light for extended periods.

CIBJO Gemstone Book 2022

CIBJO Gemstone Book §6.2:special-care code f

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

care (chemicals)2 sources compared

Amethyst — 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
Only after these treatments
fissure filling with oil, fissure filling with resin
Source & check 2026-09-25
Source
Fact checked on
2026-09-25

Amethyst — care (chemicals): Hydrofluoric acid, ammonium fluoride and alkaline solutions can damage it.

GIA Gem Encyclopedia (care guide)

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

care (wear)2 sources compared

Amethyst — care (wear): Avoid knocking it in use, or small fissures may form, especially where facets meet.

CIBJO Retailers' Reference Guide (2021)

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

Amethyst — care (wear): Mohs 7 with good toughness, fine for any jewellery including rings, but everyday dust is mostly quartz, so guard it against scratches.

GIA Gem Encyclopedia (care guide)

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

Amethyst — care (special care): heated to lighten colour or remove smoky tones: special care (SC); some unheated material may fade in long sunlight.

AGTA Gemstone Information Manual, 17th ed.

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

Amethyst — care (setting): prong and bezel: relatively safe; channel: use caution; flush and pavé: avoid.

Gems & Gemology 1987 (Martin)

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

Amethyst — care (repair): polishing: use caution; jeweller's torch, pickle pot and thermal shock: avoid; note: strong heat can bleach it colourless or turn amethyst into citrine and back; avoid thermal shock.

Gems & Gemology 1987 (Martin)

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

Amethyst — care (display): heat in the display case, sunlight and artificial light: relatively safe; note: amethyst may fade with long exposure to strong light and heat.

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 Amethyst: CIBJO states that treated stones, specifically those with fractures filled with oil or resin, must not be cleaned ultrasonically; Martin's Gemstone Durability states that for untreated stones ultrasonic and steam cleaning call for caution; GIA states that, whatever the treatment state, warm soapy water is safe and ultrasonic cleaning is usually fine, except for the rare dyed or fracture-filled stone. Heat: GIA states that, whatever the treatment state, sudden temperature changes can crack Amethyst, and it should not be heated. Chemicals: CIBJO states that treated stones, specifically those with fractures filled with oil or resin, should be kept away from solvents, chemicals and high temperatures; GIA states that, whatever the treatment state, hydrofluoric acid, ammonium fluoride and alkaline solutions will damage Amethyst. Light: CIBJO states that untreated stones may fade or revert to their original colour under strong light. Wear: GIA states that, whatever the treatment state, it has a Mohs hardness of 7 and good toughness, and should be protected from scratches in everyday wear.

This table scrolls sideways on narrow screens.

QuestionMatching entries
Can it go in an ultrasonic or steam cleaner?care (cleaning); ultrasonic and steamer: use caution; note: avoid thermal shock; Warm soapy water is safe; ultrasonic cleaning is usually fine except for the rare dyed or fracture-filled stone; steam cleaning is not advised
Heat and thermal shockSudden temperature changes can crack it, and it should not be heated; polishing: use caution; jeweller's torch, pickle pot and thermal shock: avoid; note: strong heat can bleach it colourless or turn amethyst into citrine and back; avoid thermal shock
Light and displaymay fade or revert to its original colour in strong light; do not wear or leave it in strong light for extended periods; heat in the display case, sunlight and artificial light: relatively safe; note: amethyst may fade with long exposure to strong light and heat
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; Hydrofluoric acid, ammonium fluoride and alkaline solutions can damage it
Wearing limits (knocks, settings)Avoid knocking it in use, or small fissures may form, especially where facets meet; Mohs 7 with good toughness, fine for any jewellery including rings, but everyday dust is mostly quartz, so guard it against scratches; prong and bezel: relatively safe; channel: use caution; flush and pavé: avoid

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.

untreated

any treatment state

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

treated (Only after these treatments: heating)

Durability and wearing

Toughness

Good toughness

Sources GIA Gem Encyclopedia (care guide)

Treatments and identification leads

One row per treatment, with three standards side by side: how often it occurs and how stable it is (CIBJO), its category in GB/T 16552—2017 Table B.1 (this site's paraphrase) and how the JJA/AGL 2025 table lists it. Each CIBJO value links to its entry under “Testing and market”, where the wording and source are given in full.

This table scrolls sideways on narrow screens.

TreatmentMarket frequency (CIBJO)Stability (CIBJO)GB/T 16552 categoryJJA/AGL listingIdentification leads
fissure filling with resinStatus: treatedrarelyunstable———
fissure filling with oilStatus: treatedoccasionallyunstable———
heatingStatus: treated——Optimization—See identification leads
Irradiation——Optimization——
Filling——Graded — see §5.4.1, Table 1——
Dyeing——Treatment——
Coating——Treatment——

Where each treatment acts (schematics): Filled / Fracture-filled · Heated / Heat-treated

“—” means the cited source gives no value for that item, not “none”. Source: CIBJO Gemstone Book 2022 · GB/T 16553—2017; GB/T 16552—2017 Table B.1 (row for Rock Crystal); 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

A general LMHC wording rule also covers Amethyst (Information Sheet #8): see the LMHC rule “When colour authenticity cannot be determined”.

VerifyNames, standards, technical facts, clauses and sources

Names

Chinese standard nameThe Chinese formal name of Amethyst is given in GB/T 16552—2017 Table A.1, where the GB/T formal-name entry reads Amethyst (GB/T formal); the mineralogical name is Quartz (SiO₂), purple variety. Trade and mineralogical namesThe common Chinese market name differs from the formal one. Recommended listing nameThe suggested listing name gives the market name together with the formal name; both correspond to Amethyst in English. Names in four languagesThe four-language names are the Simplified and Traditional Chinese names, English Amethyst and the Japanese names; the GSJ (Japan) formal name is the katakana form. National standard namesAmong national and regional formal names, Germany (RAL) uses Amethyst, the European Union Amethyst and France (DGCCRF) Améthyste. Institution usageFor authority wording, GIA, FTC and CIBJO record Amethyst, with the qualifier (quartz variety) stripped from the CIBJO headline name; Gem-A is unchecked, and bodies without a recorded wording show the entry's own English name, which does not represent their position.

Authority wording

GIA, FTC, CIBJO, Gem-A
Amethyst (on record for GIA, FTC, CIBJO; Gem-A unchecked — bodies without a recorded wording show the entry's own English name)
GSJ (Japan) formal name
アメシスト
Chinese formal name
紫晶 (GB/T 16552—2017 Table A.1)
Mineralogical name
Quartz (SiO₂), purple variety
GB/T formal-name entry
紫晶 / Amethyst (GB/T formal)

Four-language names

简体中文
紫水晶
繁體中文
紫水晶
English
Amethyst
日本語
アメシスト／紫水晶

National and regional formal names

Germany (RAL)
Amethyst
European Union
Amethyst
France (DGCCRF)
Améthyste

Qualifiers stripped from the headline name

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

Classification

Origin
Natural materials
Material domain
Natural inorganic gem materials
Browsing family
Quartz and chalcedony materials
Identity tier
Mineral / gemstone variety
Mineral chemical class
Silicates
Construction or treatment status
Natural; common industry optimization (verify with certificate)

Treatments listed by standards

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

Under the “Rock Crystal” row of Table B.1: Heating Optimization; Irradiation Optimization; Filling Graded — see §5.4.1, Table 1; Dyeing Treatment; Coating Treatment. The full row, with the effect column, is on the Rock Crystal page.

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
AmethystQuartzviolet to reddish violetan untreated tier is listed

JJA/AGL definitions and nomenclature (2025 revision), table of principal gem names, p.10

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

What it is and how it's identified

The composition (phase) of Amethyst is quartz. The following values are taken from the clause for rock crystal (the whole class), not measured on Amethyst alone: structure crystalline, trigonal, with hexagonal prismatic crystals showing pronounced horizontal striations on the prism faces; Mohs hardness 7, cleavage none; density 2.64–2.69 g/cm³, a range derived from the clause value 2.66 and its permitted tolerance (+0.03, −0.02); refractive index 1.544–1.553, birefringence 0.009; optical character anisotropic, uniaxial, positive, a "bull's-eye" interference figure may appear, and Brazil-law twinning is common in amethyst; untreated, pleochroism is weak and varies with colour, the body colour is light to dark purple, and the lustre is vitreous. The untreated body colour is also given in CIBJO wording as bluish violet to violet to reddish purple.

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”.

Chemical composition, luminescence, UV-visible spectrum, infrared spectrum, magnification: these whole-class features are given in the cited clause for rock crystal (the whole class), so they are not repeated on the Amethyst page; see the material facts on the Rock Crystal entry.

Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of Amethyst (how to read class-level values).

Definition

Amethyst — composition (phase): quartz

CIBJO Gemmological Laboratories Book 2024

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

Structure

Amethyst — structure (overall): crystalline

GB/T 16553—2017

Does this standard apply
applies to this entry
What this covers
rock crystal (the whole class)
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
Fact checked on
2026-09-26

Amethyst — structure (crystal system): trigonal

GB/T 16553—2017

Does this standard apply
applies to this entry
What this covers
rock crystal (the whole class)
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
Fact checked on
2026-09-26

Amethyst — structure (crystal habit): hexagonal prisms with prominent horizontal striations on the prism faces

GB/T 16553—2017

Does this standard apply
applies to this entry
What this covers
rock crystal (the whole class)
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
Fact checked on
2026-09-26

Durability

Amethyst — Mohs hardness: 7

GB/T 16553—2017

123456789107References (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
What this covers
rock crystal (the whole class)
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
Fact checked on
2026-09-26

Amethyst — cleavage: none

GB/T 16553—2017

Does this standard apply
applies to this entry
What this covers
rock crystal (the whole class)
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
Fact checked on
2026-09-26

For Amethyst, the stability of fissure filling with resin is “unstable”.

CIBJO Gemstone Book 2022

Treatment state
treated
Treatment
fissure filling with resin
Qualification

This says how well the treatment holds up, not how durable Amethyst itself is.

General note
no durability verdict here
Source & check 2026-09-22
Source
Fact checked on
2026-09-22

For Amethyst, the stability of fissure filling with oil is “unstable”.

CIBJO Gemstone Book 2022

Treatment state
treated
Treatment
fissure filling with oil
Qualification

This says how well the treatment holds up, not how durable Amethyst itself is.

General note
no durability verdict here
Source & check 2026-09-22
Source
Fact checked on
2026-09-22

Physical properties

Amethyst — density: 2.64–2.69 g/cm³

GB/T 16553—2017

0.51.52.53.54.55.56.57.52.64–2.69
Specific gravitySource: GB/T 16553—2017
Does this standard apply
applies to this entry
What this covers
rock crystal (the whole class)
Qualification

The clause we cite gives 2.66, with a stated tolerance of +0.03 / -0.02. The range shown here is worked out from that.

Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
Fact checked on
2026-09-26

Optical

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

Amethyst — optic character: Amethyst commonly shows Brazil-law twinning

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 Optic character · Amethyst (locator checked 2026-09-28)
Fact checked on
2026-09-26

Amethyst — optic character: anisotropic material, uniaxial, with positive optic character; a “Bull's eye” interference figure may be present, and Brazil-law twinning is common in amethyst.

GB/T 16553—2017

Does this standard apply
applies to this entry
What this covers
rock crystal (the whole class)
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
Fact checked on
2026-09-26

Amethyst — refractive index: 1.544–1.553

GB/T 16553—2017

1.31.72.12.52.93.31.544–1.553
Refractive indexSource: GB/T 16553—2017
Does this standard apply
applies to this entry
What this covers
rock crystal (the whole class)
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
Fact checked on
2026-09-26

Amethyst — birefringence: 0.009

GB/T 16553—2017

00.050.10.150.20.250.30.009
BirefringenceSource: GB/T 16553—2017
Does this standard apply
applies to this entry
What this covers
rock crystal (the whole class)
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
Fact checked on
2026-09-26

Amethyst — pleochroism: weak; it depends on the body colour.

GB/T 16553—2017

Treatment state
untreated
Does this standard apply
applies to this entry
What this covers
rock crystal (the whole class)
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
Fact checked on
2026-09-26

Amethyst — optical effect (chatoyancy): seen

GB/T 16553—2017

Does this standard apply
applies to this entry
What this covers
rock crystal (the whole class)
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
Fact checked on
2026-09-26

Amethyst — optical effect (asterism): seen; a six-rayed star, common in rose quartz.

GB/T 16553—2017

Does this standard apply
applies to this entry
What this covers
rock crystal (the whole class)
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
Fact checked on
2026-09-26

body colour2 sources compared

Amethyst — body colour: Violet to purple to reddish purple.

CIBJO Gemmological Laboratories Book 2024

Treatment state
untreated
Qualification

In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Colour-change Sapphire, Taaffeite, Spinel and other entries also name violet or a violetish colour.

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

Amethyst — body colour: light to dark violet

GB/T 16553—2017

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

In chapter 5 of GB/T 16553—2017, the colour entries of Ruby, Lazulite, Axinite and other variety clauses also name purple or a purplish colour.

General note
colour alone is not identity
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 Colour · Amethyst (locator checked 2026-09-28)
Fact checked on
2026-09-26

How the sources relate

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

complementary, no conflict

Both give violet. GB/T 16553—2017 describes the depth (light to dark), the CIBJO Gemmological Laboratories Book the range of hue (violet to purple to reddish purple).

CIBJO definitions
chatoyancy, asterism

Quality factors

Amethyst — quality factor (lustre): vitreous

GB/T 16553—2017

Treatment state
untreated
Does this standard apply
applies to this entry
What this covers
rock crystal (the whole class)
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (locator checked 2026-09-26)
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.

1.531.541.551.561.571.582.52.62.72.82.9Refractive indexSpecific gravity12345Amethyst

This material (RI / SG midpoints): 1.548 / 2.67; Closest values: 1Agate 1.537 / 2.63, 2Shoushan Stone 1.56 / 2.7, 3Changhua Stone 1.56 / 2.6, 4Bamboo Coral 1.57 / 2.65, 5Synthetic Beryl 1.57 / 2.69

Show the full chart (330 registered materials)1.41.51.61.71.81.922.12.22.32.41234567Refractive indexSpecific gravity12345Amethyst

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 lead for heat treatment in Amethyst is that, when heated, deeply coloured amethyst becomes lighter, and may also turn into citrine or green quartz; after heat treatment the colour of quartz gems is stable and hard to detect. GB/T 16553—2017, which this heat-treatment lead cites, serves only as a reference and does not govern directly. Synthetic amethyst is common on the market. Among amethyst in circulation, fissure filling with resin is rare and fissure filling with oil is occasional. CIBJO's laboratory rules place amethyst under quartz; identification is covered in the quartz entry, and the list of required methods is on the laboratory testing page.

The CIBJO laboratory protocol covers Amethyst under “Quartz” (§6.1.65): see identification on the Quartz entry; the required tests are listed on the CIBJO laboratory protocol table for Quartz.

How far testing can go

Amethyst that has undergone heating can be identified by the following features: Dark amethyst may become lighter on heating, and amethyst may turn into citrine or green quartz; heated quartz gems are stable in colour and not easy to detect.

GB/T 16553—2017

Treatment state
treated
Does this standard apply
can be followed as a reference only
Treatment
heating
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.1.16 (heating) (locator checked 2026-09-26)
Fact checked on
2026-09-26

Amethyst — synthetic counterpart on the market: Synthetic counterparts of this material are common in the trade

CIBJO Gemstone Book 2022

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

For Amethyst in trade, the reported frequency of fissure filling with resin is “rarely”.

CIBJO Gemstone Book 2022

Treatment state
treated
Treatment
fissure filling with resin
Source & check 2026-09-22
Source
Fact checked on
2026-09-22

For Amethyst in trade, the reported frequency of fissure filling with oil is “occasionally”.

CIBJO Gemstone Book 2022

Treatment state
treated
Treatment
fissure filling with oil
Source & check 2026-09-22
Source
Fact checked on
2026-09-22

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

Clause-level definitions

Amethyst has clause-level definitions registered in CIBJO Gemmological Laboratories Book 2024. The term Amethyst is defined as the violet to purple to reddish purple variety of quartz; the term Quartz is defined as the mineral species quartz, IMA status A, with the CIBJO wording quoted in full under Clause-level definitions on this page. Both are defined directly by CIBJO and also appear in the GB/T annex.

This table scrolls sideways on narrow screens.

TermClauseDefinitionCross-check
Amethyst7.2.1.10Violet to purple to reddish purple variety of quartzDefined directly by CIBJO; also present in the GB/T annex.
Quartz7.2.1.190see amethyst, ametrine, citrine, dumortierite quartz, iris quartz, morion, prasiolite, rock crystal, rose quartz, rutilated quartz, sagenitic quartz, smoky quartz, tourmalinated quartz, aventurine quartzDefined 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 “Amethyst” · Source
GB/T 16552—2017
Naming rule 5.1.1 a) · Source
CIBJO Gemmological Laboratories Book 2024
Listed §7.2.1.10 “Amethyst” · Source
CIBJO Gemmological Laboratories Book 2024
Listed §7.2.1.190 “Quartz” · Source
IMA Mineral List 2026-07
Listed “Quartz” · Source

Sources

Further reading

Related pages

Treatments recorded for this material

Recorded cultural contexts

Birthstone list

The U.S. Jewelers of America roster lists Amethyst for February; the U.K. National Association of Jewellers chart lists Amethyst as traditional for February; and Japan's JJA 2021 revised roster lists Amethyst for February. 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, February row: Amethyst
Japan Jewellery AssociationJapanfrom 20 December 2021Tanjoseki (Japanese birthstone roster, Japan Jewellery Association page; revision of 20 December 2021)
2021 revised birthstone roster, February row: Amethyst
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, February row: Amethyst (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 Quartz on this site: 74 entries listed by this site's parent-entry links; synthetic, treated and similar entries carry their recorded state after the name; this page (Amethyst) is marked.

This table scrolls sideways on narrow screens.

PageContentStatus
Browsing familyQuartz and chalcedony materialsLive
Treatments recorded for this materialHeated / Heat-treated, Irradiated (via parent material), Filled / Fracture-filled (via parent material), Dyed (via parent material), Coated (via parent material)Live
Related articlesTo be added (placeholder)Planned

Who maintains this page

The material facts in the Amethyst 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 2026-09-22 and 2026-09-26
Last revised
2026-10-13
Purpose
Lets buyers and sellers check naming, disclosure and material facts clause by clause.

Spotted an error? Report it on the forum