On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Mineral group / supergroup · Natural identity; treatment status unknown
Tourmaline
Also known asBi-coloured Tourmaline · Parti-coloured Tourmaline · Tri-coloured Tourmaline
A borosilicate mineral supergroup of complex composition; its GB/T basic name and its mineral name are two different Chinese terms, both rendered in English as Tourmaline; irradiation or heat treatment may alter its colour. 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.
Questions people ask about Tourmaline
Every sentence below is followed by the registered fact it rests on; answers add no new facts and promise no outcome.
Q1Why does tourmaline come in so many colours, often in one crystal?
Its colour relates to trace elements such as iron, manganese and lithium and to growth zoning: as the pegmatite fluid evolves it can leave colour bands within a single crystal, producing the common multicoloured or zoned tourmaline.G&G Summer 2025It occurs in many colours, and different zones of a single crystal can be two-coloured or multicoloured.GB/T 16553—2017It is often named with a colour prefix, and parti-coloured, bi-coloured and tri-coloured stones also occur.CIBJO Gemmological Laboratories Book 2024
Q2Is there synthetic tourmaline, and how is real tourmaline identified?
No synthetic tourmaline is commercially available.CIBJO Gemstone Book 2022Its pleochroism is moderate to strong, showing lighter and deeper shades of the body colour.GB/T 16553—2017Its crystals are rounded trigonal prisms or more complex prism-and-pyramid combinations, with faces distinctly striated lengthwise.GB/T 16553—2017In the mid-infrared it shows its own diagnostic band pattern.GB/T 16553—2017Glass imitations exist: in one laboratory case, prisms shaped like Paraíba tourmaline crystals were glass with a single refractive index of 1.50, a specific gravity of 2.43 and trapped gas bubbles.G&G Winter 2020Whether one particular bead is natural, treated or synthetic — only a laboratory report can settle that.What this page can answer
Q3Is tourmaline durable enough for an everyday ring?
Yes, with care: rated 7–7.5 in Mohs hardness and fair in toughness, tourmaline can be worn daily if it is guarded against scratches and knocks; the chief dangers are heat, which can alter its colour, and abrupt temperature swings, which can crack it.GIA Gem Encyclopedia (care guide)Heavily included stones may have weak zones, and some bi-coloured stones are weaker along the colour boundary.CIBJO Retailers' Reference Guide (2021)Prong, bezel and channel settings call for caution, and flush and pavé are best avoided.Gems & Gemology 1987 (Martin)
Q4How should you clean tourmaline, and can it get wet?
Warm soapy water is best; ultrasonic and steam cleaners are not advised.GIA Gem Encyclopedia (care guide)It is generally unaffected by chemicals, but heat harms it: high heat can shift the colour and thermal shock can fracture it.GIA Gem Encyclopedia (care guide)Stones with colourless oil or resin in voids need special care, away from temperature changes and steaming.AGTA Gemstone Information Manual, 17th ed.
Q5Where does tourmaline form?
Mainly in granitic pegmatites, which are its representative formation environment.G&G Summer 2025Granitic pegmatites crystallize from residual magmatic fluid rich in water and volatiles, and boron, phosphorus and fluorine together with excess water are key conditions for a magma to generate them.G&G Summer 2025The residual fluid becomes progressively enriched in boron and fluxing components, allowing tourmaline to crystallize.G&G Summer 2025Gem crystals are mainly recovered from open or clay-filled pockets in the core and central zones of the pegmatite.G&G Summer 2025The cited texts give no specific growth duration or absolute age for tourmaline crystals.G&G Summer 2025
Q6Is tourmaline heated or irradiated, and do the colours last?
Yes: heating dark tourmaline can lighten the colour, and the result is stable and hard to detect.GB/T 16553—2017Irradiating pale pink, pale yellow, green, blue or colourless tourmaline can produce deep pink to red, deep purple-red, yellow to orange-yellow or green, but the colour is not stable, fades easily on heating, and the treatment is hard to detect.GB/T 16553—2017Colours produced by irradiation can fade with heat or bright light.GIA Gem Encyclopedia (care guide)Fillers are also used; under magnification the filled area may show a different lustre, a flash effect and gas bubbles.GB/T 16553—2017
Q7Does tourmaline fade in sunlight?
Generally not: tourmaline is generally stable to light.GIA Gem Encyclopedia (care guide)Display-case heat, sunlight and artificial light are rated relatively safe.Gems & Gemology 1987 (Martin)The exception is irradiated colour, which can fade with heat or bright light.GIA Gem Encyclopedia (care guide)
Q8What makes good-quality tourmaline?
According to GIA, tourmaline quality depends on its colour family.GIA Tourmaline Quality FactorsAmong the most sought-after colours is the pink to red variety known as rubellite; green tourmalines at their best are transparent, brilliant and clean, with attractive bluish green hues.GIA Tourmaline Quality FactorsClarity expectations also differ by colour: red tourmalines with some eye-visible inclusions are usually tolerated if the colour is strong and attractive, whereas green tourmalines are expected to be free of eye-visible inclusions.GIA Tourmaline Quality Factors
Q9What are Paraíba, rubellite and watermelon tourmaline?
Laboratories in the LMHC define Paraíba tourmaline as blue, green or greenish tourmaline coloured mainly by copper and manganese, from any origin, while low-saturation stones with only traces of copper are not called Paraíba.LMHC Information Sheet #6Rubellite is a trade name for pink to red tourmaline, and watermelon tourmaline is colour-zoned, pink in the centre and green outside.GIA Tourmaline Description
Q10What does tourmaline symbolize, and does it have healing powers?
There is no scientific evidence that tourmaline 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 an October birthstone: Jewelers of America and Japan's JJA list it for October, and the U.K. National Association of Jewellers lists pink tourmaline as an alternative for October.Cultural recordsMuseum objects include a 12th-century Iranian ring set with a tourmaline bead and a Panamanian Coclé pendant of 950–1100 CE recorded as gold and tourmaline.The Met 1980.541.6 · The Met 1979.206.733 +4
Sources cited in these answers ASA/CAP guidance (UK)
What this page can answer
This page covers
- How Tourmaline forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify TourmalineIdentification points from the research literature; how far lab testing can go and whether a synthetic exists
- Treatments and enhancements of Tourmaline6 registered treatments: status, stability, how common they are and identification leads
- Caring for and wearing TourmalineCleaning, heat, chemicals and light, as the cited sources give them; durability indicators and wearing advice
- Hardness, density and refractive index of TourmalineEach value with its source and check date
- Tourmaline in English, Chinese and Japanese; national standard namesNames in four languages, the GB/T standard name and the suggested listing name, names in national standards; and: Which of GIA, FTC, CIBJO and Gem-A have a name for it on record, and do those agree?
- Name origin and history of TourmalineWhere the name comes from; how people have used it, with museum objects
- Listing and disclosing TourmalineThe listing name to use; what must be disclosed before sale
- Standard clauses that define TourmalineWhich clause defines it, each cross-checked
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
Tourmaline (the tourmaline supergroup) is a gem material whose most important formation environment is granitic pegmatite. Pegmatites crystallize from a small volume of residual, water- and volatile-rich magmatic fluid left during the final stages of crystallization of a granitic magma, and gem-quality crystals commonly grow in open pockets within the core and central zones. Because boron is a principal constituent of tourmaline itself, the boron-rich residual pegmatite fluid provides a key condition for its crystallization.
Scope: Covers the predominantly granitic-pegmatite origin of natural gem-quality tourmaline (including elbaite and tourmaline gems); does not cover tourmaline of metamorphic origin or treated material.
Sources G&G Summer 2025
Where it forms
Shallow-crustal granitic pegmatite bodies (dikes, sills, lenses), typically within or near the upper portions of a related granitic pluton
Sources G&G Summer 2025
Residual hydrous, volatile-rich (B, P, F) magmatic fluid during the final stage of crystallization
Sources G&G Summer 2025
How it forms, step by step
A small volume of residual, water- and volatile-rich magmatic fluid separates during the final stages of granitic magma crystallization
The fluid crystallizes in place within the pluton or in fractures of the country rock, cooling from the outside inward
The residual fluid becomes progressively enriched in incompatible elements such as boron and in fluxing components, allowing minerals such as tourmaline to crystallize
Gem-quality, large tourmaline crystals grow in open pockets in the core and central zones
Link to appearance
Tourmaline colour relates to trace elements (e.g. Fe, Mn, Li) and to growth zoning; the evolving pegmatite fluid can leave colour bands within a single crystal, producing the common multi-coloured or zoned tourmaline.
Sources G&G Summer 2025
Timescale
The cited authoritative texts do not state a specific growth duration or absolute age for tourmaline crystals; pegmatite crystallization is described as a single magmatic process proceeding from the outside inward.
Sources G&G Summer 2025
Supporting findings
Tourmaline is one of the significant gem minerals of granitic pegmatites, which are its representative formation environment.
Evidence grade AScope: The source is a GIA pegmatite review that lists gem tourmaline alongside beryl, spodumene, etc.; it does not distinguish individual species within the tourmaline supergroup.
Granitic pegmatites crystallize from residual water- and volatile-rich magmatic fluid, and the presence of boron, phosphorus and fluorine together with excess water is a key condition for a magma to generate pegmatites.
Evidence grade AScope: This is the general precondition for a magma to form pegmatites; the source does not tie it specifically to tourmaline crystallization, though it is consistent with tourmaline's boron content.
Within a pegmatite body, gem-bearing crystals are mainly recovered from pockets — open or filled with clay — situated in the core and central zones.
Evidence grade AScope: This describes the general occurrence of gem crystals in pegmatites, covering tourmaline and others; 'most often' is an empirical generalisation with exceptions.
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Africa
- Kenya
Sources GIA Gem Encyclopedia
- Madagascar
Sources GIA Gem Encyclopedia
- Mozambique
Sources GIA Gem Encyclopedia
Asia
- Afghanistan
Sources GIA Gem Encyclopedia
- Pakistan
Sources GIA Gem Encyclopedia
North America
- California, United States
Sources GIA Gem Encyclopedia
- Maine, United States
Sources GIA Gem Encyclopedia
South America
- Minas Gerais, Brazil
Sources GIA Gem Encyclopedia
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.
Where the name comes from
Laboratories in the LMHC define Paraíba tourmaline as blue, bluish green to greenish blue, green or yellowish green tourmaline of medium-light to high saturation and tone, coloured mainly by copper and manganese, from any geographical origin. Tourmaline with only traces of copper and low saturation, or with a colour outside that range, is not called Paraíba.
Evidence grade AScope: Describes how the cited standard or laboratory body defines the name; trade usage and other bodies may differ, and whether a given stone qualifies can only be decided by laboratory testing.
Sources LMHC Information Sheet #6
Rubellite is a trade name for pink, red, purplish red, orangy red or brownish red tourmaline, though some in the trade argue it should not apply to pink stones. Watermelon tourmaline is colour-zoned, pink in the centre and green around the outside, and is typically cut in slices to show the arrangement.
Evidence grade BScope: Describes trade names as reported by one educational source; they are not formal standards.
Sources GIA Tourmaline Description
Human use and museum objects
The Met's Iranian ring (1980.541.6, 12th century) is set with a tourmaline bead and its Panamanian Coclé double crocodile pendant (1979.206.733, 950–1100 CE) is 'Gold, tourmaline'; further Qing to modern Chinese and Western jewels are labelled 'tourmaline', including colour-variety terms such as pink and green tourmaline.
Evidence grade AScope: Based only on the museum's cataloguing of these specific objects; it is not generalized to widespread practice or universal use of the material.
Sources The Met 1980.541.6 · The Met 1979.206.733 · The Met 21.175.127 +3
- The Metropolitan Museum of Art — Ring (1980.541.6)
- The Metropolitan Museum of Art — Double crocodile pendant (1979.206.733)
- The Metropolitan Museum of Art — Pendant with floral designs (21.175.127)
- The Metropolitan Museum of Art — Snuff Bottle (50.145.218a, b)
- The Metropolitan Museum of Art — Necklace (48.187.551)
- Cleveland Museum of Art — Mandarin Chain Bead Necklace (1945.167)
Objects are recorded under 'tourmaline', often distinguishing colour varieties. The earliest is The Met's Iranian ring (1980.541.6, 12th century), set with a tourmaline bead, and its Panamanian Coclé (Macaracas) double crocodile pendant (1979.206.733, 950–1100 CE), 'Gold, tourmaline'. The rest are chiefly Qing and modern pieces: Met 21.175.127 pendant (China, Qing, 'Tourmaline'); Met 50.145.218a, b snuff bottle (China, Qing, 18th century, 'Tourmaline'); Cleveland 1945.167 'Mandarin Chain Bead Necklace' (China, Qing, 1800s, 'tourmaline, jade, pearls…'). The museum also records colour varieties, e.g. Met 48.187.551 'Pink tourmaline', 48.187.550 'Green tourmaline' and 2011.10.2 'green tourmalines'; these colour-variety terms follow the museum's wording, tourmaline itself covering a wide colour range.
Sources The Met 1980.541.6 · The Met 1979.206.733 · The Met 21.175.127 +3
- The Metropolitan Museum of Art — Ring (1980.541.6)
- The Metropolitan Museum of Art — Double crocodile pendant (1979.206.733)
- The Metropolitan Museum of Art — Pendant with floral designs (21.175.127)
- The Metropolitan Museum of Art — Snuff Bottle (50.145.218a, b)
- The Metropolitan Museum of Art — Necklace (48.187.551)
- Cleveland Museum of Art — Mandarin Chain Bead Necklace (1945.167)
Scope: A museum object evidences only that artefact's existence and date; it does not establish widespread ancient use of the material, nor does it authenticate the origin, naturalness or treatment of any modern specimen.
Objects cited
- The Met 1980.541.6Gold; cast and fabricated from sheet, decorated with bitumen-highlighted incising, set with tourmaline bead
- The Met 1979.206.733Gold, tourmaline
- The Met 21.175.127Tourmaline
- The Met 50.145.218a, bTourmaline
- The Met 48.187.551Pink tourmaline
- Cleveland Museum of Art 1945.167tourmaline, jade, pearls, seed pearls, seed coral and gilt metal
Cultural records for this material: Birthstone list.
How it is identified
In one laboratory case, two bluish green prisms with metallic inclusions, shaped to resemble copper-bearing Paraíba tourmaline crystals, were manufactured glass: they had a single refractive index of 1.50 and a specific gravity of 2.43, and the microscope showed trapped gas bubbles, flow structure and a boundary where two glasses had been fused.
Evidence grade AScope: 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 Winter 2020
Other research findings
Tourmaline quality depends on its colour family. Among the most sought-after colours is the pink to red variety known as rubellite; green tourmalines at their best are transparent, brilliant and clean, with attractive bluish green hues.
Evidence grade BScope: Quality factors as described by one educational source; not a grading standard and not a statement about the value of any piece.
Sources GIA Tourmaline Quality Factors
Clarity expectations differ by colour: red tourmalines with some eye-visible inclusions are usually tolerated if the colour is strong and attractive, whereas green tourmalines are expected to be free of eye-visible inclusions.
Evidence grade BScope: Quality factors for coloured gem tourmaline as described by one educational source; not a grading standard, not a statement about the value of any piece, and not about opaque black tourmaline (schorl).
Sources GIA Tourmaline Quality Factors
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- Formation evidence rests on a single GIA pegmatite review and does not separate the formation conditions of individual tourmaline-supergroup species.
- The source gives no absolute ages or growth-rate data for tourmaline crystallization.
Methodology
- Origin determination and its limits
- Quality grading and value factors
- How gemmology became a technical discipline
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
- Tourmaline
GB/T 16552—2017 Table A.1 “Tourmaline” · CIBJO Gemmological Laboratories Book 2024 §7.2.1.244 “Tourmaline”
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Heated / Heat-treated, Filled / Fracture-filled, Irradiated, 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
Tourmaline is often subjected to heating, filling and irradiation.
Under GB/T 16552-2017, heating counts as an optimization, so the plain gem name may be used (§5.4.2.1 a); 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); irradiation counts as a treatment and must be stated in the name (§5.4.2.2 a). Do not assume it is unenhanced.
What this means for you
Before buying, check the recommended listing name "Tourmaline" and any disclosed treatments on this page, and ask the seller for a grading report if in doubt.
Known uncertainty
- This entry's exact material identity is not fully settled.
- See “Disclosure and cautions” above
- Disclosure rules for the treatments above can change as authorities update their standards; re-check before relying on this page.
- Last reviewed
- 2026-09-01
Trade-name ruling
- Industry-wide term that does not denote a single species.
- Suggested listing name
- Tourmaline
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
Tourmaline — care (cleaning): Warm soapy water is best; ultrasonic and steam cleaners are not advised.
GIA Gem Encyclopedia (care guide)
- Treatment state
- any treatment state
Source & check 2026-09-26
- Source
- GIA Gem Encyclopedia — Tourmaline Care and Cleaning Guide: Section “Cleaning” (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Tourmaline — care (cleaning): ultrasonic and steamer: use caution; note: avoid thermal shock.
Gems & Gemology 1987 (Martin)
- Treatment state
- untreated
Source & check 2026-09-26
- Source
- Martin, “Gemstone Durability: Design to Display”, Gems & Gemology, Summer 1987: pp.66–67 fold-out chart, Tourmaline row, CLEANING column (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Tourmaline — 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
- filling, fissure filling with oil, fissure filling with resin
Source & check 2026-09-26
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, Tourmaline, p.80-85; §6.2 j (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Tourmaline — care (heat): generally stable to light and unaffected by chemicals, but heat harms it: high heat can shift the colour and thermal shock can fracture it.
GIA Gem Encyclopedia (care guide)
- Treatment state
- any treatment state
Source & check 2026-09-26
- Source
- GIA Gem Encyclopedia — Tourmaline Care and Cleaning Guide: Section “Stability” (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Tourmaline — care (light): Colours produced by irradiation can fade with heat or bright light; colours from heat treatment are stable, and the treatment cannot be detected.
GIA Gem Encyclopedia (care guide)
- Treatment state
- treated
- Only after these treatments
- irradiation
Source & check 2026-09-26
- Source
- GIA Gem Encyclopedia — Tourmaline Care and Cleaning Guide: Section “Stability” (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Tourmaline — 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
- filling, fissure filling with oil, fissure filling with resin
Source & check 2026-09-26
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, Tourmaline, p.80-85; §6.2 k (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
care (wear)2 sources compared
Tourmaline — care (wear): Mohs 7 to 7.5 with fair toughness
GIA Gem Encyclopedia (care guide)
- Treatment state
- any treatment state
Source & check 2026-09-26
- Source
- GIA Gem Encyclopedia — Tourmaline Care and Cleaning Guide: Section “Hardness and toughness” (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Tourmaline — care (wear): hard enough, but heavily included stones may have weak zones, and some bi-colours are weaker along the colour boundary.
CIBJO Retailers' Reference Guide (2021)
- Treatment state
- any treatment state
Source & check 2026-09-26
- Source
- CIBJO Retailers' Reference Guide — Gemstones (November 2021) (CIBJO): p.69, Tourmaline chapter, “Cutting, care and cleaning” (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Tourmaline — care (special care): heated for colour (yellow to orange, green to blue, pink, red and purple): normal care.
AGTA Gemstone Information Manual, 17th ed.
- Treatment state
- treated
- Only after these treatments
- heating
Source & check 2026-09-26
- Source
- AGTA Gemstone Information Manual, 17th edition (August 2026) (AGTA): p.XV–XVI, Gemstone Information Chart, Tourmaline Yellow/Orange H, Green/Blue H, Pink/Red/Purple H, CARE REQUIRED / SPECIAL ADVICE (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Tourmaline — care (special care): chrome- and vanadium-coloured stones and tourmaline cat's-eyes (untreated): normal care.
AGTA Gemstone Information Manual, 17th ed.
- Treatment state
- untreated
Source & check 2026-09-26
- Source
- AGTA Gemstone Information Manual, 17th edition (August 2026) (AGTA): p.XV, Gemstone Information Chart, Tourmaline Chrome / Vanadium N, Cat’s Eye N, CARE REQUIRED / SPECIAL ADVICE (locator checked 2026-09-28)
- Fact checked on
- 2026-09-26
Tourmaline — care (special care): colourless oil or resin in voids (green-blue, pink-red-purple): special care (SC); avoid temperature changes and steaming.
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
- AGTA Gemstone Information Manual, 17th edition (August 2026) (AGTA): p.XVI, Gemstone Information Chart, Tourmaline Green/Blue O, Pink/Red/Purple O, CARE REQUIRED / SPECIAL ADVICE (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Tourmaline — care (special care): colouring agents in voids (pink-red-purple): special care (SC); keep it from temperature swings, steam, chemicals and ultrasonic cleaning.
AGTA Gemstone Information Manual, 17th ed.
- Treatment state
- treated
- Only after these treatments
- dyeing
Source & check 2026-09-26
- Source
- AGTA Gemstone Information Manual, 17th edition (August 2026) (AGTA): p.XVI, Gemstone Information Chart, Tourmaline Pink/Red/Purple D, CARE REQUIRED / SPECIAL ADVICE (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Tourmaline — care (special care): irradiated for colour (yellow to orange, pink, red and purple): normal care.
AGTA Gemstone Information Manual, 17th ed.
- Treatment state
- treated
- Only after these treatments
- irradiation
Source & check 2026-09-26
- Source
- AGTA Gemstone Information Manual, 17th edition (August 2026) (AGTA): p.XV–XVI, Gemstone Information Chart, Tourmaline Yellow/Orange R, Pink/Red/Purple R, CARE REQUIRED / SPECIAL ADVICE (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Tourmaline — care (setting): prong, bezel and channel: use caution; flush and pavé: avoid; note: parti-coloured stones tend to break at colour boundaries; heavily included stones or those with liquid inclusions need extra care.
Gems & Gemology 1987 (Martin)
- Treatment state
- untreated
Source & check 2026-09-26
- Source
- Martin, “Gemstone Durability: Design to Display”, Gems & Gemology, Summer 1987: pp.66–67 fold-out chart, Tourmaline row, SETTING column (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Tourmaline — care (repair): polishing: use caution; jeweller's torch, pickle pot and thermal shock: avoid; note: heat changes the colour of some greens; thermal shock may break it, and parti-coloured stones may break where the colour zones meet.
Gems & Gemology 1987 (Martin)
- Treatment state
- untreated
Source & check 2026-09-26
- Source
- Martin, “Gemstone Durability: Design to Display”, Gems & Gemology, Summer 1987: pp.66–67 fold-out chart, Tourmaline row, REPAIR column (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Tourmaline — 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
- Martin, “Gemstone Durability: Design to Display”, Gems & Gemology, Summer 1987: pp.66–67 fold-out chart, Tourmaline row, DISPLAY column (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.
Common care questions and matching entries
CleaningCleaning Tourmaline: GIA states that, whatever the treatment state, warm soapy water is best and ultrasonic and steam cleaning are not advised; Martin's Gemstone Durability: Design to Display states that for untreated Tourmaline ultrasonic and steam cleaning call for caution; CIBJO states that treated stones, specifically those that are filled or have fractures filled with oil or resin, must not be cleaned ultrasonically. Heat: GIA states that, whatever the treatment state, high temperatures can change the colour. Light: GIA states that for treated stones, specifically irradiated ones, irradiation-induced colour can fade with heat or strong light. Chemicals: CIBJO states that treated stones, specifically those that are filled or have fractures filled with oil or resin, should be kept away from all solvents, chemicals and high temperatures; AGTA states that treated stones, specifically dyed ones, should be kept away from steam cleaning, chemicals and ultrasonic cleaning. Wear: GIA states that, whatever the treatment state, Tourmaline has a Mohs hardness of 7–7.5; Martin's Gemstone Durability: Design to Display states that for untreated Tourmaline, prong, bezel and channel settings call for caution, and tension and pavé settings should be avoided.
This table scrolls sideways on narrow screens.
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
- Warm soapy water is best; ultrasonic and steam cleaners are not advised
- generally stable to light and unaffected by chemicals, but heat harms it: high heat can shift the colour and thermal shock can fracture it
- Mohs 7 to 7.5 with fair toughness
- hard enough, but heavily included stones may have weak zones, and some bi-colours are weaker along the colour boundary
untreated
- ultrasonic and steamer: use caution; note: avoid thermal shock
- chrome- and vanadium-coloured stones and tourmaline cat's-eyes (untreated): normal care
- prong, bezel and channel: use caution; flush and pavé: avoid; note: parti-coloured stones tend to break at colour boundaries; heavily included stones or those with liquid inclusions need extra care
- polishing: use caution; jeweller's torch, pickle pot and thermal shock: avoid; note: heat changes the colour of some greens; thermal shock may break it, and parti-coloured stones may break where the colour zones meet
- heat in the display case, sunlight and artificial light: relatively safe
treated (Only after these treatments: filling, fissure filling with oil, fissure filling with resin)
- care (cleaning) §6.2 j
- Treatments with dye, oil, resin, wax or plastic are not permanent; keep it away from all solvents (including dish-washing liquids), chemicals and heat §6.2 k
treated (Only after these treatments: irradiation)
- Colours produced by irradiation can fade with heat or bright light; colours from heat treatment are stable, and the treatment cannot be detected
- irradiated for colour (yellow to orange, pink, red and purple): normal care
treated (Only after these treatments: heating)
treated (Only after these treatments: fissure filling with oil, fissure filling with resin)
treated (Only after these treatments: dyeing)
Durability and wearing
Toughness
Fair
Sources GIA Gem Encyclopedia (care guide)
Treatments and identification leads
Registered treatmentsThe registered treatments for Tourmaline are fissure filling with oil, filling, irradiation, dyeing, heat treatment and coating. Stability and frequencyFissure filling with oil has the status treated, its stability is unstable, and it occurs occasionally on the market; filling, heat treatment and coating all have the status treated; irradiation has the status irradiated or dyed; and dyeing has the status colour treated. Values not givenFor filling, irradiation, dyeing, heat treatment and coating, stability and frequency are recorded as a dash, meaning the cited source gives no value, not none.
This table scrolls sideways on narrow screens.
| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| fissure filling with oilStatus: treated | occasionally | unstable | — | — | — |
| fillingStatus: treated | — | — | Graded — see §5.4.1, Table 1 | — | See identification leads |
| irradiationStatus: irradiated or dyed | — | — | Treatment | — | See identification leads |
| dyeingStatus: colour treated | — | — | Treatment | — | See identification leads |
| heatingStatus: treated | — | — | Optimization | — | See identification leads |
| coatingStatus: treated | — | — | Treatment | — | See identification leads |
Where each treatment acts (schematics): Filled / Fracture-filled · Irradiated · Dyed · Heated / Heat-treated · Coated
“—” 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; 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 Tourmaline (Information Sheet #0): see the LMHC rule “What every report states”.
A general LMHC wording rule also covers Tourmaline (Information Sheet #8): see the LMHC rule “When colour authenticity cannot be determined”.
VerifyNames, standards, technical facts, clauses and sources
Names
Besides Tourmaline, the name register records "Bi-coloured Tourmaline", "Parti-coloured Tourmaline", "Tourmaline" and "Tri-coloured Tourmaline", for which no restriction on use as a name is recorded (CIBJO Gemstone Book 2022 Annex 8 “Bi-coloured”; JJA/AGL Gemstone Nomenclature 2025 p.15; CIBJO Gemstone Book 2022 Annex 8 “tri-coloured Tourmaline”); 2 further names in non-Latin scripts are listed in the name register below (2 with no restriction recorded on use as a name).
Standard and listing namesThe GB/T 16552—2017 formal name for Tourmaline is given in Table A.1, the suggested listing name is Tourmaline, and a registered synonym is the Chinese mineral name for tourmaline; Tourmaline is also recorded as a trade name/synonym, and in the name register Tourmaline is a market name. Institution usageOn authority wording, GIA and CIBJO wording is recorded (for CIBJO, see the Gemmological Laboratories Book 2024), the FTC text on file has no wording for Tourmaline (checked), and Gem-A is unchecked; bodies without a recorded wording show the entry's own English name, which does not represent their position. National standard namesGermany (RAL) writes Turmalin, and the EU and France (DGCCRF) both write Tourmaline. Names in four languagesNames are given in four languages: Simplified Chinese, Traditional Chinese, English (Tourmaline) and Japanese (a katakana transliteration and a kanji name); Japan's GSJ formal name is recorded in the same way. Candidate search termsThe name register also includes Bi-coloured Tourmaline and Tri-coloured Tourmaline from the CIBJO Gemstone Book 2022, and Parti-coloured Tourmaline with its Japanese transliteration from the Japanese JJA/AGL Gemstone Nomenclature 2025, the Japanese transliteration serving only as a search candidate. Trade and mineralogical namesThe mineralogical name is Tourmaline supergroup, borosilicates of complex composition.
Name register
Every name recorded for this entry, with how it is classified, whether it may be matched to this entry automatically, whether it may be used as a product name, and the clause it rests on.
This table scrolls sideways on narrow screens.
| Name | Type | Matching | Use as a name | Basis |
|---|---|---|---|---|
| no restriction recorded (6) | ||||
| Bi-coloured TourmalineEnglish | narrower name (variety or subtype) | matched automatically | no restriction recorded | CIBJO Gemstone Book 2022 Annex 8 “Bi-coloured” |
| Parti-coloured TourmalineEnglish | narrower name (variety or subtype) | matched automatically | no restriction recorded | JJA/AGL Gemstone Nomenclature 2025 p.15 |
| TourmalineEnglish | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
| Tri-coloured TourmalineEnglish | narrower name (variety or subtype) | matched automatically | no restriction recorded | CIBJO Gemstone Book 2022 Annex 8 “tri-coloured Tourmaline” |
| パーティカラード・トルマリンJapanese | transliteration | search candidate only | no restriction recorded | JJA/AGL Gemstone Nomenclature 2025 p.15 |
| 电气石Simplified Chinese | synonym | matched automatically | no restriction recorded | GB/T 16552—2017 Table A.1 “Tourmaline” |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- トルマリン／電気石
- Chinese formal name
- 碧玺 (GB/T 16552—2017 Table A.1)
- Mineralogical name
- Tourmaline supergroup (complex borosilicates)
- Trade names and synonyms
- Parti-coloured Tourmaline (narrower name (variety or subtype)) · Bi-coloured Tourmaline (narrower name (variety or subtype)) · Tri-coloured Tourmaline (narrower name (variety or subtype))
Four-language names
- 简体中文
- 碧玺
- 繁體中文
- 碧璽
- English
- Tourmaline
- 日本語
- トルマリン／電気石
National and regional formal names
- Germany (RAL)
- Turmalin
- European Union
- Tourmaline
- France (DGCCRF)
- Tourmaline
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural inorganic gem materials
- Browsing family
- Tourmaline-supergroup minerals and gem varieties
- Identity tier
- Mineral group / supergroup
- Mineral chemical class
- Silicates
- Construction or treatment status
- Natural identity; treatment status unknown
Treatments listed by standards
GB/T Table B.1In the “Tourmaline” row of GB/T 16552—2017 Annex B, Table B.1, heating improves colour and is in the optimization category; filling improves or changes durability and appearance, its category defined by the standard's grades; dyeing improves or changes colour, in the treatment category; irradiation changes colour, in the treatment category; and coating improves or changes lustre, colour and other aspects of appearance, in the treatment category. The notes to Table B.1 and the definitions of the filling grades are on the Gem treatments page. JJA/AGL designationsThe Japanese JJA/AGL 2025 designations list Tourmaline under the species tourmaline with colour recorded as other colours and a no-treatment category; they also list Parti-coloured Tourmaline under the species tourmaline, with colour recorded as two or more distinct colours with clear colour boundaries, and a no-treatment category. Parti-coloured Tourmaline has no entry of its own on this site and is listed under the parent entry.
GB/T 16552-2017, Annex B, Table B.1
Table B.1, row “Tourmaline” (p.14):
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| Method | Effect | Category |
|---|---|---|
| Heating | Improves colour | Optimization |
| Filling | Improves or changes durability and appearance | Graded — see §5.4.1, Table 1 |
| Dyeing | Improves or changes colour | Treatment |
| Irradiation | Changes colour | Treatment |
| Coating | Improves or changes lustre, colour and other aspects of appearance | Treatment |
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 name | Species | Colour | Listed in the table | Notes |
|---|---|---|---|---|
| [colour] Tourmaline | Tourmaline | other colours | an untreated tier is listed | |
| Parti-coloured Tourmaline | Tourmaline | two or more distinct colours with sharp boundaries | an untreated tier is listed | no dedicated entry on this site; shown on the broader entry |
JJA/AGL definitions and nomenclature (2025 revision), table of principal gem names, p.15
How to read the JJA/AGL table: see the Gem treatments page.
What it is and how it's identified
The composition (phase) of Tourmaline is the tourmaline group; structure crystalline, trigonal, with rounded trigonal prismatic or ditrigonal pyramidal-prismatic crystals and pronounced longitudinal striations on the crystal faces. Mohs hardness 7–8, where the site note explains that hardness alone is not enough to judge durability; cleavage none. Density 2.46–3.26 g/cm³, a range derived from the clause value 3.06 and its permitted tolerance of +0.20/−0.60. Optical character anisotropic, uniaxial, negative; refractive index 1.615–1.655, a range derived from the clause value 1.624–1.644 and its permitted tolerance of +0.011/−0.009; birefringence 0.018–0.04, where the site note explains that the clause has finer sub-ranges and the overall value is registered. Untreated Tourmaline has moderate to strong pleochroism, in darker and lighter shades of the body colour; untreated Tourmaline has vitreous lustre; the cat's-eye effect can occur, and the colour-change effect can occur but is rare.
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
Tourmaline — composition (phase): tourmaline group
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Structure
Tourmaline — 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): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline — structure (crystal system): trigonal
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): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline — structure (crystal habit): rounded trigonal prisms or more complex ditrigonal prism-and-pyramid combinations; the crystal faces are distinctly striated lengthwise.
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): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Durability
Tourmaline — Mohs hardness: 7–8
GB/T 16553—2017
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))
- 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): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline — cleavage: none
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): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
For Tourmaline, 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 Tourmaline itself is.
- General note
- no durability verdict here
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Physical properties
Tourmaline — density: 2.46–3.26 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 3.06, with a stated tolerance of +0.20 / -0.60. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Optical
Tourmaline — 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): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline — refractive index: 1.615–1.655
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 1.624–1.644, with a stated tolerance of +0.011 / -0.009. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline — birefringence: 0.018–0.04
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- General note
- the clause has finer ranges
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline — pleochroism: moderate to strong, in lighter and deeper shades of the body colour.
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): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline — fluorescence (overall): generally none; red and pink tourmaline: weak, red to violet.
GB/T 16553—2017
UV fluorescenceredvioletweak, red and pink tourmalineDots 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): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline — spectrum (UV-visible): red and pink tourmaline: broad absorption band in the green region; sometimes visible 525 nm narrow absorption band; 451 nm absorption peak; 458 nm absorption peak; blue and green tourmaline: general absorption in the red region; 498 nm strong absorption band.
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): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline — spectrum (infrared): In the mid-IR, tourmaline shows its own diagnostic band pattern.
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): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline — 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): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline — optical effect (colour change): 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): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline — magnification: gas-liquid inclusions, mineral inclusions, growth striations, color band, irregularly shaped tube inclusions, parallel line-like inclusions, visible doubling of facet edges (birefringence).
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): §5.1.10 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
body colour2 sources compared
Tourmaline — body colour: Tourmaline is often named with a colour prefix; there are also parti-coloured, bi-coloured and tri-coloured tourmaline and cat’s-eye tourmaline, showing chatoyancy and typically with green, blue or pink body colour.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Aquamarine, Chrysocolla, Dioptase and other entries also name green or a greenish colour.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- Fact checked on
- 2026-09-26
Tourmaline — body colour: any of many colors, and a single crystal can be two-colored or multicolored in different zones.
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- Qualification
GB/T 16553—2017 sums up the colour of Tourmaline as “all colours”; in its chapter 5, Calcite, Opal, Quartzite Jade and other variety clauses likewise say “all colours” or “all body colours”.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.10 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
How the sources relate
- CIBJO Gemmological Laboratories Book 2024 and GB/T 16553—2017
Both describe tourmaline as coming in many colours, including two or more colours in one stone (the CIBJO Gemmological Laboratories Book says parti-, bi- and tri-coloured). The CIBJO Gemmological Laboratories Book adds that tourmaline is often named by a colour prefix and that cat's-eye tourmaline is typically green, blue or pink.
- CIBJO definitions
- chatoyancy, colour change
Quality factors
Tourmaline — 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): §5.1.10 (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.
This material (RI / SG midpoints): 1.635 / 2.86; Closest values: 1Prehnite 1.625 / 2.88, 2Larimar 1.62 / 2.82, 3Datolite 1.646 / 2.95, 4Danburite 1.633 / 3, 5Sugilite 1.61 / 2.77
Show the full chart (330 registered materials)
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
Testing and market
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: §6.1.86.
How far testing can go
Tourmaline that has undergone filling can be identified by the following features: Under magnification the exposed part of the filler has a surface luster differing from that of the host stone, and the filled area may show a flash effect and gas bubbles; infrared spectra show characteristic absorption bands of the filler; luminescence imaging (such as a UV fluorescence viewer) 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 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.10 (filling) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline that has undergone irradiation can be identified by the following features: Irradiating pale pink, pale yellow, green, blue or colourless tourmaline can produce deep pink to red, deep purple-red, yellow to orange-yellow or green; the colour is not stable, fades easily on heating, and the treatment is not easy to detect.
GB/T 16553—2017
- Treatment state
- irradiated or dyed
- Does this standard apply
- can be followed as a reference only
- Treatment
- irradiation
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.10 (irradiation) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline 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.
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): §5.1.10 (dyeing) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline that has undergone heating can be identified by the following features: Heating dark tourmaline can lighten the colour; the result is stable 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 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.10 (heating) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline 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; 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): §5.1.10 (coating) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Tourmaline — synthetic counterpart on the market: No synthetic counterpart of this material is commercially available
CIBJO Gemstone Book 2022
- Treatment state
- any treatment state
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
For Tourmaline 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
Tourmaline — notes on test methods in the CIBJO laboratory protocol:
| Test method | What the protocol notes for it |
|---|---|
| Microscope: | Fracture filling; |
| Phenomena: | Cat’s-eye, colour change; |
| EDXRF chemistry: | For Paraiba |
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
Tourmaline is defined directly in CIBJO Gemmological Laboratories Book 2024, with the registered term Tourmaline. The visible definition is that tourmaline is often named with a colour prefix. The cross-check shows it is defined directly by CIBJO, and Tourmaline also appears in the GB/T 16552—2017 annex.
This table scrolls sideways on narrow screens.
| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Tourmaline | 7.2.1.244 | Tourmaline is often named with a colour prefix; there are also parti-coloured, bi-coloured and tri- coloured tourmaline and cat’s-eye tourmaline, showing chatoyancy and typically with green, blue or pink body colour. Common variety names are specifically mentioned in this list | Defined directly by CIBJO; also present in the GB/T annex. |
Evidence and sources
Authority basis and clause sources
Sources
Further reading
Recorded cultural contexts
The U.S. Jewelers of America roster lists Tourmaline for October; the U.K. National Association of Jewellers chart lists Pink Tourmaline as an alternative for October; and Japan's JJA 2021 revised roster lists Tourmaline for October. This records trade-association convention only; it does not establish material identity, natural origin, treatment, provenance, or effect.
This table scrolls sideways on narrow screens.
| Publisher or holder | Region | From / period | Source and locator |
|---|---|---|---|
| Jewelers of America | United States | from 1952 | Jewelers of America, “Birthstone Jewelry” (web page, consulted 2026-08-22) Birthstone roster table, October row: Tourmaline |
| Japan Jewellery Association | Japan | from 20 December 2021 | Tanjoseki (Japanese birthstone roster, Japan Jewellery Association page; revision of 20 December 2021) 2021 revised birthstone roster, October row: Tourmaline |
| National Association of Jewellers | United Kingdom | — | National Association of Jewellers, “Zodiac Birthstones Jewellery: Star Signs, Gemstones and Their Meaning” (web page, consulted 2026-08-22) Zodiac birthstone chart, October row: Pink Tourmaline (Alternative) |
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 Tourmaline on this site: 12 entries listed by this site's parent-entry links; synthetic, treated and similar entries carry their recorded state after the name; this page (Tourmaline) is marked.
- Tourmaline
This table scrolls sideways on narrow screens.
| Page | Content | Status |
|---|---|---|
| Browsing family | Tourmaline-supergroup minerals and gem varieties | Live |
| Treatments recorded for this material | Heated / Heat-treated, Filled / Fracture-filled, Irradiated, Dyed, Coated | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Tourmaline 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.