On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Trade name: colour / appearance variety · Natural identity; treatment status unknown
Black Tourmaline
Also known asSchorl
A commercial colour name for black tourmaline, usually but not always the tourmaline species schorl; it is not a separate mineral species itself. 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 Black Tourmaline
Every sentence below is followed by the registered fact it rests on; answers add no new facts and promise no outcome.
Q1How can you tell if black tourmaline is real?
Colour alone cannot prove a stone is black tourmaline: CIBJO's Gemmological Laboratories Blue Book also describes magnetite, melanite and jet, among others, as black.CIBJO Gemmological Laboratories Book 2024China's national standard describes tourmaline crystals, as a group, as rounded trigonal prisms or more complex prism-and-pyramid combinations with distinct lengthwise striations.GB/T 16553—2017No synthetic black tourmaline is commercially available.CIBJO Gemstone Book 2022Whether one particular bead is natural, treated or synthetic — only a laboratory report can settle that.What this page can answer
Q2Where does black tourmaline form?
Black tourmaline, most often schorl, forms in a wide variety of rock types, such as granite, pegmatite and gneiss, commonly as an accessory mineral.GIA Tourmaline Description · G&G Summer 2025As a granitic pegmatite cools and crystallises, black tourmaline crystals grow in its central zones and pockets.GIA Tourmaline Description · G&G Summer 2025There the black schorl crystals occur together with feldspar, quartz and other minerals.GIA Tourmaline Description · G&G Summer 2025
Q3How hard is black tourmaline, and should it scratch easily?
China's national standard gives tourmaline as a group a Mohs hardness of 7–8; the figure is for the whole group, not measured on black tourmaline itself.GB/T 16553—2017The parent entry Tourmaline records that it is hard enough, but heavily included stones may have weak zones.CIBJO Retailers' Reference Guide (2021) (via parent entry Tourmaline)
Q4What makes black tourmaline black, and does any light pass through it?
Its black is an iron-related colour, and colour alone cannot establish the mineral species or any treatment.GIA Tourmaline DescriptionCIBJO's Gemmological Laboratories Blue Book describes black tourmaline as opaque.CIBJO Gemmological Laboratories Book 2024
Q5Is black tourmaline the same thing as schorl?
Usually: the name generally denotes black tourmaline, most commonly the iron-rich species schorl.GIA Tourmaline DescriptionBut black tourmaline is a colour-based name, and colour alone cannot fix the mineral species: the same dark look may belong to schorl or to other iron-rich tourmalines.GIA Tourmaline DescriptionCIBJO's Gemmological Laboratories Blue Book records its phase as schorl (tourmaline group).CIBJO Gemmological Laboratories Book 2024
Q6Does black tourmaline protect against negative energy, or have healing powers?
There is no scientific evidence that black 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)
Sources cited in these answers ASA/CAP guidance (UK)
What this page can answer
This page covers
- How Black Tourmaline forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify Black TourmalineHow far lab testing can go and whether a synthetic exists
- Treatments and enhancements of Black TourmalineThe enhancements and treatments the GB/T and JJA/AGL tables list
- Caring for and wearing Black TourmalineCleaning, heat, chemicals and light, as the cited sources give them
- Hardness, density and refractive index of Black TourmalineEach value with its source and check date
- Black Tourmaline in English, Chinese and Japanese; national standard namesNames in four languages, the GB/T standard name and the suggested listing name; and: Has any of GIA, FTC, CIBJO or Gem-A put a name for it on record here?
- Listing and disclosing Black TourmalineThe listing name to use; what must be disclosed before sale
- Standard clauses that define Black 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
Black tourmaline generally denotes black tourmaline, most commonly the iron-rich species schorl. Schorl is one species within the tourmaline supergroup and is found in a broad range of rock types, among them granite, pegmatite and gneiss, frequently as an accessory mineral; inside granitic pegmatites its black crystals sit alongside feldspar, quartz and further minerals. Black tourmaline is at heart a colour-based trade name and not an independent species, since other iron-rich tourmalines can share the same dark look.
Scope: Applies at the level of colour name/trade name for natural black tourmaline; the mineral species requires compositional analysis for confirmation, and treatment, origin and quality assessments are not covered.
Sources GIA Tourmaline Description · G&G Summer 2025
Where it forms
A wide variety of rock types (granite, pegmatite, gneiss, etc.), commonly as an accessory mineral
Sources GIA Tourmaline Description · G&G Summer 2025
Granitic pegmatite bodies, where black schorl crystals occur with feldspar, quartz and other minerals
Sources GIA Tourmaline Description · G&G Summer 2025
How it forms, step by step
Tourmaline crystallises from an iron-rich melt or fluid, and iron occupies a structural site so that the species approaches schorl
Sources GIA Tourmaline Description · G&G Summer 2025
During cooling and crystallisation of a granitic pegmatite, black tourmaline crystals grow in the central zones and pockets
Sources GIA Tourmaline Description · G&G Summer 2025
The black crystals occur together with feldspar, quartz and other minerals, forming a tourmaline assemblage common in pegmatites
Sources GIA Tourmaline Description · G&G Summer 2025
Link to appearance
Black is an iron-related colour expression; colour alone cannot establish the mineral species or any treatment.
Sources GIA Tourmaline Description
Timescale
The cited authoritative texts give no specific growth duration or absolute age for black tourmaline / schorl crystals.
Sources GIA Tourmaline Description
Related base materials
- Schorl (tourmaline supergroup): Black tourmaline usually refers to schorl; black tourmaline is a commercial/colour name based on colour, not a separate mineral species
Supporting findings
Black tourmaline generally denotes black tourmaline, most commonly the iron-rich species schorl.
Evidence grade BScope: ‘Generally’ describes the common case; black tourmaline may be other iron-rich species and needs chemical confirmation.
Sources GIA Tourmaline Description
Schorl is found in a broad range of rock types; within granitic pegmatites it appears alongside feldspar, quartz and further minerals.
Evidence grade AScope: General occurrence; the pegmatite association rests on a captioned example and does not cover all localities.
Sources GIA Tourmaline Description · G&G Summer 2025
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Africa
- Anibib and Farm Etemba, Erongo, Namibia
Sources Handbook of Mineralogy
Asia
- Nuristan, Afghanistan
Sources Handbook of Mineralogy
Europe
- St. Andreasberg, Harz Mountains, Germany
Sources Handbook of Mineralogy
- Bovey Tracey, Devon, England, United Kingdom
Sources Handbook of Mineralogy
- Elba, Tuscany, Italy
Sources Handbook of Mineralogy
- Mursinka area, Ural Mountains, Russia
Sources Handbook of Mineralogy
South America
- Minas Gerais, Brazil
Sources Handbook of Mineralogy
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.
Other research findings
Synthesis: black tourmaline is a colour-based name and colour alone cannot fix the mineral species; the same dark appearance may correspond to schorl or other iron-rich tourmalines.
Evidence grade BScope: A name-level synthesis across entries, not a specimen-level conclusion; species still requires testing.
Sources GIA Tourmaline Description
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The species of black tourmaline needs chemical analysis; this record states the common case only.
- The sources give no absolute age or growth rate for schorl crystallisation.
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
- Black Tourmaline (usually schorl)
GB/T 16552—2017 5.1.1 c) · CIBJO Gemmological Laboratories Book 2024 §7.2.1.211 “Schorl”
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Heated / Heat-treated (via parent material), Filled / Fracture-filled (via parent material), Dyed (via parent material), Irradiated (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
"Black Tourmaline" is a market name rather than a mineral species name; before using it, verify: Industry-wide term that does not denote a single species.
What this means for you
Before buying, check the recommended listing name "Black Tourmaline (usually schorl)" 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
- Last reviewed
- 2026-09-01
Trade-name ruling
- Industry-wide term that does not denote a single species.
- Suggested listing name
- Black Tourmaline (usually schorl)
Care and wear
The item-by-item care advice that the GIA Care and Cleaning Guide gives for the whole class, and so for Black Tourmaline, is set out in full under care on the Tourmaline entry.
Care
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
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.
| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| Heating | — | — | Optimization | — | — |
| Filling | — | — | Graded — see §5.4.1, Table 1 | — | — |
| Dyeing | — | — | Treatment | — | — |
| Irradiation | — | — | Treatment | — | — |
| Coating | — | — | Treatment | — | — |
“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16552—2017 Table B.1 (row for Tourmaline)
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
VerifyNames, standards, technical facts, clauses and sources
Names
Besides Black Tourmaline, the name register records "Schorl", for which no restriction on use as a name is recorded.
Chinese standard nameThe national-standard naming counterpart for Black Tourmaline is tourmaline, from GB/T 16552—2017 Table A.1; Black Tourmaline itself is not listed in the text. Trade and mineralogical namesBlack Tourmaline is a colour or appearance variety among trade names; its trade name and synonym is Schorl, the mineralogical name is usually schorl tourmaline. Recommended listing nameThe suggested listing name is Black Tourmaline (usually schorl). Names in four languagesThe names cover Simplified Chinese, Traditional Chinese, English (Black Tourmaline) and Japanese. Institution usageOn authority wording, the FTC text has no wording for the name Black Tourmaline (checked); GIA, CIBJO and Gem-A have not been checked; bodies without a recorded wording show the entry's own English name, Black Tourmaline, which does not represent the position of GIA, FTC, CIBJO or Gem-A. Japanese namesFor GSJ (Japan), the entry's own Japanese name is shown, and the GSJ's wording for that name has not yet been verified by this site.
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 (1) | ||||
| SchorlEnglish | synonym | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- ブラックトルマリン (not yet checked for this body — the entry's own Japanese name is shown)
- GB/T naming counterpart (this name is not in the standard)
- 碧玺 (GB/T 16552—2017 Table A.1)
- Mineralogical name
- Usually schorl tourmaline
- Trade names and synonyms
- Schorl (synonym)
Four-language names
- 简体中文
- 黑碧玺
- 繁體中文
- 黑碧璽
- English
- Black Tourmaline
- 日本語
- ブラックトルマリン
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
- Trade name: colour / appearance variety
- Mineral chemical class
- Silicates
- Construction or treatment status
- Natural identity; treatment status unknown
Treatments listed by standards
Treatments for Black Tourmaline are registered by applying the “Tourmaline” row of GB/T 16552—2017 Annex B, Table B.1, as the standard has no separate row for Black Tourmaline: heating is classed as optimization; filling is defined by separate grades; dyeing, irradiation and coating are all classed as treatment. The full effect column is on the Tourmaline entry; what Table B.1 notes and how the filling grades are defined are explained on this site's Gem treatments page.
GB/T 16552-2017, Annex B, Table B.1
Under the “Tourmaline” row of Table B.1: Heating Optimization; Filling Graded — see §5.4.1, Table 1; Dyeing Treatment; Irradiation Treatment; Coating Treatment. The full row, with the effect column, is on the Tourmaline 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.
What it is and how it's identified
Among the registered material facts for Black Tourmaline, the composition (phase) is black tourmaline (tourmaline group), transparency is opaque, and the body colour is black, with treatment status untreated; this site notes that in Chapter 7 of the CIBJO Gemmological Laboratories Book the colour descriptions of entries such as magnetite, melanite and jet also mention black or blackish colours. Values taken from tourmaline (the whole mineral group): crystalline, trigonal; Mohs hardness 7–8; density 2.46–3.26 g/cm³, derived from the clause value of 3.06 with an allowed deviation of +0.20/−0.60; optically anisotropic, uniaxial, negative; refractive index 1.615–1.655, derived from the clause value of 1.624–1.644 with an allowed deviation of +0.011/−0.009; birefringence 0.018–0.04, the clause also having finer sub-ranges, with the overall value registered; pleochroism moderate to strong, in darker and lighter shades of the body colour, treatment status untreated; lustre vitreous, treatment status untreated.
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”.
Luminescence, UV-visible spectrum, infrared spectrum, magnification: these whole-class features are given in the cited clause for tourmaline (the whole mineral group), so they are not repeated on the Black Tourmaline page; see the material facts on the Tourmaline entry.
Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of Black Tourmaline (how to read class-level values).
Definition
Black Tourmaline — nomenclature status: IMA status Rn: renamed (a mineral already known, given a new name in the IMA era).
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Black Tourmaline — composition (phase): schorl (tourmaline group)
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Structure
Black Tourmaline — structure (overall): crystalline
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- tourmaline (the whole mineral group)
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
Black Tourmaline — structure (crystal system): trigonal
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- tourmaline (the whole mineral group)
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
Black 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
- What this covers
- tourmaline (the whole mineral group)
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
Durability
Black 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
- What this covers
- tourmaline (the whole mineral group)
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
Black Tourmaline — cleavage: none
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- tourmaline (the whole mineral group)
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
Physical properties
Black Tourmaline — density: 2.46–3.26 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- tourmaline (the whole mineral group)
- 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
Black Tourmaline — optic character: uniaxial, optically negative (anisotropic)
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- tourmaline (the whole mineral group)
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
Black Tourmaline — refractive index: 1.615–1.655
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- tourmaline (the whole mineral group)
- 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
Black Tourmaline — birefringence: 0.018–0.04
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- tourmaline (the whole mineral group)
- 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
Black Tourmaline — transparency: opaque.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Black 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
- What this covers
- tourmaline (the whole mineral group)
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
Black Tourmaline — optical effect (chatoyancy): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- tourmaline (the whole mineral group)
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
Black Tourmaline — optical effect (colour change): seen; rare
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- tourmaline (the whole mineral group)
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
Black Tourmaline — body colour: black.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Magnetite, Melanite, Jet and other entries also name black or a blackish colour.
- General note
- colour alone is not identity
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
- CIBJO definitions
- chatoyancy, colour change
Quality factors
Black Tourmaline — quality factor (lustre): vitreous
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- tourmaline (the whole mineral group)
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
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
Identification of Black Tourmaline falls under the Tourmaline line of the CIBJO laboratory protocol; see the identification section of the Tourmaline entry, and the list of required methods on the laboratory testing page. No synthetic counterpart of Black Tourmaline is available on the market.
The CIBJO laboratory protocol covers Black Tourmaline under “Tourmaline” (§6.1.86): see identification on the Tourmaline entry; the required tests are listed on the CIBJO laboratory protocol table for Tourmaline.
How far testing can go
Black 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
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Clause-level definitions
Black Tourmaline is defined directly in the gem materials list of CIBJO Gemmological Laboratories Book 2024 under the entry Schorl; the entry name is Schorl and the definition is black, opaque. The cross-check result is that it is defined directly by CIBJO, and no identically named English entry was found in this edition of the GB/T annex.
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| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Schorl | 7.2.1.211 | black, opaque | Defined directly by CIBJO; no identically named English entry was found in this edition of the GB/T annex. |
Evidence and sources
Authority basis and clause sources
Sources
- CIBJO – The World Jewellery Confederation. Gemmological Laboratories Book (Blue Book), Gemmological Commission 2024-1.
- CIBJO – The World Jewellery Confederation. The Gemstone Book (Blue Book), 2022.
- SAMR / SAC (China). GB/T 16552—2017 Gems — Nomenclature.
- GIA – Gemological Institute of America (United States). Gem Encyclopedia: Tourmaline Description.
Further reading
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 (Black Tourmaline) is marked.
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 (via parent material), Filled / Fracture-filled (via parent material), Dyed (via parent material), Irradiated (via parent material), Coated (via parent material) | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Black 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.