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UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Mineral species · Natural identity; treatment status unknown
Kyanite
Also known asDisthene
A mineral species with composition Al2SiO5 and GB/T basic name Kyanite; its hardness varies with direction and it is brittle, and its colour does not indicate that it is untreated. 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.
What this page can answer
This page covers
- How Kyanite forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify KyaniteHow far lab testing can go and whether a synthetic exists
- Treatments and enhancements of Kyanite2 registered treatments: status, stability, how common they are and identification leads
- Caring for and wearing KyaniteCleaning, heat, chemicals and light, as the cited sources give them; durability indicators and wearing advice
- Density and refractive index of KyaniteEach value with its source and check date
- Kyanite in English, Chinese and Japanese; national standard namesNames in four languages, the GB/T standard name and the suggested listing name; 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 KyaniteWhere the name comes from
- Listing and disclosing KyaniteThe listing name to use; what must be disclosed before sale
- Standard clauses that define KyaniteWhich 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
Kyanite, formula Al2SiO5, is triclinic and usually develops bladed, tabular crystals that are frequently bent or twisted. It is found in gneiss, schist, quartz veins and enclosed pegmatites, having grown during regional metamorphism at moderately high pressure that acted mainly on pelitic rocks; in addition it occurs as a detrital mineral in sedimentary rocks. Kyanite, andalusite and sillimanite together make up the three polymorphs of Al2SiO5: kyanite occupies the moderately high-pressure field, in contrast to low-pressure andalusite and high-temperature sillimanite.
Scope: Applies to describing the origin, composition and occurrence of kyanite as the high-pressure polymorph mineral species of Al2SiO5, and explains its pressure–temperature differences from andalusite and sillimanite; does not cover synthetic or imitation materials.
Sources Handbook of Mineralogy
Where it forms
Regional metamorphism at moderately high pressure, acting mainly on pelitic rocks
Sources Handbook of Mineralogy
Gneiss, schist, quartz veins and pegmatites enclosed within them
Sources Handbook of Mineralogy
Detrital occurrence in sedimentary rocks
Sources Handbook of Mineralogy
How it forms, step by step
Aluminous pelitic sediments undergo regional metamorphism under moderately high-pressure (moderate-to-high P) conditions.
Sources Handbook of Mineralogy
Under these pressure–temperature conditions, Al and Si crystallize the Al2SiO5 kyanite phase (rather than low-pressure andalusite or high-temperature sillimanite).
Sources Handbook of Mineralogy
Kyanite occurs in gneisses, schists, pegmatites and quartz veins, commonly associated with staurolite, andalusite, sillimanite, talc, hornblende, gedrite, mullite and corundum.
Sources Handbook of Mineralogy
After weathering, kyanite may enter sedimentary rocks as a detrital mineral.
Sources Handbook of Mineralogy
Link to appearance
Kyanite is commonly dark blue but may be white, grey, yellow, pink or black and can be zoned, with a vitreous to pearly luster; its bladed, knife-like crystals, two cleavages intersecting at about 79°, and its directional hardness anisotropy (Mohs 5.5 along [001] versus Mohs 7 along [100]) together shape its appearance and working behaviour.
Sources Handbook of Mineralogy
Timescale
The source states no absolute geological timescale for kyanite formation.
Sources Handbook of Mineralogy
Supporting findings
Kyanite is found in gneiss, schist, quartz veins and enclosed pegmatites, having grown during regional metamorphism at moderately high pressure in mainly pelitic rocks, and it also occurs as a detrital mineral in sedimentary rocks.
Evidence grade BScope: Describes kyanite's general metamorphic setting and pressure regime; it does not infer P-T values for any specimen.
Sources Handbook of Mineralogy
Kyanite is commonly associated with staurolite, andalusite, sillimanite, talc, hornblende, gedrite, mullite and corundum.
Evidence grade BScope: Describes common kyanite associations; not every locality contains all of these minerals.
Sources Handbook of Mineralogy
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Africa
- KenyaOrigin of reference samples in GIA's Gübelin Gem Project
Sources GIA Gübelin Gem Project
- MadagascarOrigin of reference samples in GIA's Gübelin Gem Project
Sources GIA Gübelin Gem Project
- TanzaniaOrigin of reference samples in GIA's Gübelin Gem Project
Sources GIA Gübelin Gem Project
- ZimbabweOrigin of reference samples in GIA's Gübelin Gem Project
Sources GIA Gübelin Gem Project
Asia
- Daha, Suneri, Jajarkot and Barah, west-northwest of Kathmandu, NepalSmall-scale mining since 1999
Sources Gems & Gemology Fall 2013 · GIA Gübelin Gem Project
- MyanmarOrigin of reference samples in GIA's Gübelin Gem Project
Sources GIA Gübelin Gem Project
Europe
- SwitzerlandOrigin of reference samples in GIA's Gübelin Gem Project
Sources GIA Gübelin Gem Project
South America
- BrazilOrigin of reference samples in GIA's Gübelin Gem Project
Sources GIA Gübelin Gem Project
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
Kyanite owes its name to a Greek word for 'blue', a reference to the deep blue shade it commonly shows.
Evidence grade BScope: The etymology explains only the origin of the name; it does not establish the material's composition, locality, naturalness, or treatment.
Sources Handbook of Mineralogy
Other research findings
Kyanite has the formula Al2SiO5 and is triclinic; together with andalusite and sillimanite it forms the three Al2SiO5 polymorphs.
Evidence grade BScope: Describes kyanite's composition and polymorphic relations; not a compositional analysis of any specimen.
Sources Handbook of Mineralogy
Among the three Al2SiO5 polymorphs, kyanite forms under moderately high-pressure regional metamorphism, distinct from low-pressure-stable andalusite and high-temperature-stable sillimanite.
Evidence grade BScope: States kyanite's pressure–temperature distinction from the other two polymorphs; it gives no precise phase-boundary P-T values.
Sources Handbook of Mineralogy
Kyanite is commonly dark blue (its name derives from the Greek for blue), and may also be white, grey, yellow, pink or black, and can be zoned.
Evidence grade BScope: Describes kyanite's colour varieties and the origin of its name; it does not infer its chromophore.
Sources Handbook of Mineralogy
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The source states no absolute geological timescale for kyanite formation.
- The source describes its pressure regime only as 'moderately high-pressure regional metamorphism' and gives no precise phase-boundary P-T values.
- The chromophore of kyanite's blue colour (e.g. Fe, Ti or charge transfer) is not explicitly attributed by this source, so no chromophore attribution is made.
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
- Kyanite
GB/T 16552—2017 Table A.1 “Kyanite” · CIBJO Gemmological Laboratories Book 2024 §7.2.1.125 “Kyanite”
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Dyed, Filled / Fracture-filled
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
Kyanite is Kyanite (Al2SiO5); use "Kyanite" for listings, and disclose any known treatments.
What this means for you
Before buying, check the recommended listing name "Kyanite" 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
Kyanite — care (cleaning): Some stones are susceptible to damage from ultrasonic cleaning. Do not expose them to ultrasonic cleaning.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code j
- Treatment state
- any treatment state
Source & check 2026-09-25
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, Kyanite, p.60; §6.2 j (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
Kyanite — care (wear): low hardness, so it scratches easily; wear with care; cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code a, special-care code b
- Treatment state
- any treatment state
Source & check 2026-09-25
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, Kyanite, p.60; §6.2 a, b (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
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
Care for Kyanite: the CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) states that Kyanite must not be cleaned ultrasonically; Kyanite has low hardness and scratches easily, so wear it with care; and Kyanite breaks easily, so wear it with care. The cleaning and wear conclusions both apply to any treatment state.
This table scrolls sideways on narrow screens.
| Question | Matching entries |
|---|---|
| Can it go in an ultrasonic or steam cleaner? | care (cleaning) |
| Wearing limits (knocks, settings) | low hardness, so it scratches easily; wear with care; cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care |
Durability and wearing
Mohs hardness
Mohs 5.5 (parallel to [001]) / Mohs 7 (parallel to [100])
Treatments and identification leads
Registered treatmentsThe registered treatments for Kyanite are dyeing and filling. Dyeing has the status colour-treated, and filling the status treated. Values not givenThe cited sources give no stability or prevalence for either dyeing or filling, shown as “—”, which does not mean “none”. Identification cluesThe identification lead for dyeing is uneven colour distribution visible under magnification, often gathered in fractures or surface depressions, with no distinct pleochroism. The identification leads for filling are that under magnification the filled areas differ in lustre from the host stone and gas bubbles can be seen in them, infrared spectroscopy can detect the characteristic bands of the filler, and luminescence imaging equipment such as a UV fluorescence viewer can show where the filler is distributed.
This table scrolls sideways on narrow screens.
| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| dyeingStatus: colour treated | — | — | Treatment | — | See identification leads |
| fillingStatus: treated | — | — | Graded — see §5.4.1, Table 1 | — | See identification leads |
Where each treatment acts (schematics): Dyed · Filled / Fracture-filled
“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16553—2017; GB/T 16552—2017 Table B.1
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 Kyanite, the name register records "Disthene", for which no restriction on use as a name is recorded; one further name in a non-Latin script is listed in the name register below (1 that must not be used as a name).
Standard and listing namesThe Chinese formal name for Kyanite comes from GB/T 16552—2017 Table A.1; the suggested listing name is Kyanite, matching the CIBJO Gemmological Laboratories Book 2024, which lists it as Kyanite. Trade and mineralogical namesThe mineralogical name is Kyanite (Al2SiO5), and the trade name and synonym is Disthene. Japanese namesGSJ (Japan) has a Japanese formal name, and Japanese names are recorded; the Simplified and Traditional Chinese names are recorded, and the English name is Kyanite. Candidate search termsA Chinese market name meaning blue crystal serves only as a candidate search term and may not be used as a name; it is an example of the confusing or ambiguous naming that GB/T 16552—2017 says should not be used, not a trade name. Institution usageOn authority wording, CIBJO lists Kyanite; the FTC text on file has no wording for Kyanite (checked); GIA and Gem-A are unchecked. Bodies without a recorded wording show the entry's own English name, which does not represent their position.
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) | ||||
| DistheneEnglish | synonym | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
| not to be used as a name (1) | ||||
| 蓝晶Simplified Chinese | market name | search candidate only | not to be used as a name | GB/T 16552—2017 5.1.2.1 d); Note: GB/T 16552—2017 §5.1.2.1 d) uses it as the example of a rule: confusing or ambiguous names must not be used (a counter-example, not a trade name). |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- 藍晶石
- Chinese formal name
- 蓝晶石 (GB/T 16552—2017 Table A.1)
- Mineralogical name
- Kyanite (Al2SiO5)
- Trade names and synonyms
- Disthene (synonym)
Four-language names
- 简体中文
- 蓝晶石
- 繁體中文
- 藍晶石
- English
- Kyanite
- 日本語
- カイヤナイト／藍晶石
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural inorganic gem materials
- Browsing family
- Other silicate minerals
- Identity tier
- Mineral species
- Mineral chemical class
- Silicates
- Construction or treatment status
- Natural identity; treatment status unknown
Treatments listed by standards
The “Kyanite” row of GB/T 16552—2017 Annex B, Table B.1 lists dyeing and filling for Kyanite: dyeing improves or changes colour and is classed as treatment; filling improves or changes durability and appearance, and its category is defined by the filling grades of the cited standard. 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
Table B.1, row “Kyanite” (p.15):
This table scrolls sideways on narrow screens.
| Method | Effect | Category |
|---|---|---|
| Dyeing | Improves or changes colour | Treatment |
| Filling | Improves or changes durability and appearance | Graded — see §5.4.1, Table 1 |
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
Registered material facts for Kyanite include: chemical composition Al2SiO5, which may contain elements such as Cr, Fe, Ca, Mg and Ti; crystalline and triclinic, with a crystal habit usually prismatic and twinning common; one set of perfect cleavage and one set of moderate cleavage. Density is 3.56–3.69 g/cm³, the cited clause giving 3.68 with an allowed deviation of +0.01/−0.12, from which the limits are derived; the refractive index is 1.712–1.735, the cited clause giving 1.716–1.731 with an allowed deviation of ±0.004, from which the limits are derived; birefringence is 0.012–0.017; optically anisotropic, biaxial and negative; transparent to translucent. Untreated kyanite shows moderate pleochroism in blue: colourless, dark blue and violet-blue, with a vitreous lustre. For body colour, GB/T 16553—2017 records light to dark blue, green, yellow, grey, brown, colourless and others, while the CIBJO entry records blue, bluish green, green, yellow to red and colourless.
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
Kyanite — nomenclature status: IMA status A: approved (accepted by the IMA after it was set up in 1958).
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Kyanite — composition (chemistry): Al2SiO5, elements such as Cr,Fe,Ca,Mg and Ti may be contained.
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): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite — composition (phase): kyanite
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Structure
Kyanite — 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): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite — structure (crystal system): triclinic
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): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite — structure (crystal habit): usually prismatic; twins are common
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): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Durability
Kyanite — cleavage: one perfect and one moderate cleavage direction
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Physical properties
Kyanite — density: 3.56–3.69 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 3.68, with a stated tolerance of +0.01 / -0.12. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Optical
Kyanite — optic character: biaxial, 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): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite — refractive index: 1.712–1.735
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 1.716–1.731, with a stated tolerance of ±0.004. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite — birefringence: 0.012–0.017
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): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite — transparency: transparent, translucent.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Kyanite — pleochroism: in blue material, moderate: colourless, dark blue and purple-blue.
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): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite — fluorescence (long-wave UV): weak, red
GB/T 16553—2017
UV fluorescence (long-wave UV)redweakDots 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): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite — fluorescence (short-wave UV): none
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): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite — spectrum (UV-visible): 435 nm absorption band; 445 nm 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): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite — spectrum (infrared): The mid-IR spectrum carries kyanite's own diagnostic bands
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): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite — 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): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite — magnification: gas-liquid inclusions, mineral inclusions, cleavage, color band.
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): §5.1.28 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
body colour2 sources compared
Kyanite — body colour: light to dark blue, green, yellow, grey, brown and colorless.
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 Hemimorphite, Chrysoberyl, Kornerupine and other variety clauses also name blue or a bluish colour.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.28 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Kyanite — body colour: Blue, blue-green, green, yellow to red, colourless.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Euclase, Zircon, Kornerupine and other entries also name blue or a bluish colour.
- General note
- colour alone is not identity
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
How the sources relate
- GB/T 16553—2017 and CIBJO Gemmological Laboratories Book 2024
Both list blue, green, yellow and colourless. The CIBJO Gemmological Laboratories Book also lists blue-green and yellow to red; GB/T 16553—2017 also lists grey and brown and gives blue as light to dark.
- CIBJO definitions
- chatoyancy
Quality factors
Kyanite — 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): §5.1.28 (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): 1.724 / 3.62; Closest values: 1Rhodochrosite 1.707 / 3.58, 2Alexandrite 1.749 / 3.73, 3Sinhalite 1.688 / 3.48, 4Vesuvianite / Idocrase 1.711 / 3.38, 5Epidote 1.737 / 3.38
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
Dyed Kyanite can be recognised under magnification by uneven colour, mostly gathered in fractures or surface depressions, with no obvious pleochroism; filled Kyanite can be recognised under magnification by filled areas differing in lustre from the host and gas bubbles in the filling, by characteristic filler bands in the infrared spectrum, and by luminescence imaging equipment such as UV fluorescence viewers showing where the filler lies. These leads for dyeing and filling are cited from GB/T 16553—2017, which can only be used as a reference for Kyanite and does not govern it directly. No synthetic counterpart of Kyanite is available on the market. The CIBJO laboratory protocol's note on testing methods for Kyanite is: special optical effects, chatoyancy and colour change. The tests the CIBJO laboratory protocol requires for Kyanite, and what each method means, are in the protocol table on the laboratory testing page.
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: §6.1.48.
How far testing can go
Kyanite 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): §5.1.28 (dyeing) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite that has undergone filling can be identified by the following features: Under magnification the surface luster of the filled part differs from that of the host stone and gas bubbles are visible in the filled area; 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): §5.1.28 (filling) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Kyanite — 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
Kyanite — notes on test methods in the CIBJO laboratory protocol:
| Test method | What the protocol notes for it |
|---|---|
| Phenomena: | Cat’s eye, colour change |
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
Kyanite is defined directly in CIBJO Gemmological Laboratories Book 2024 under the entry name Kyanite, defined as mineral species kyanite with IMA status A, noting that the CIBJO wording is quoted in full under Clause-level definitions on this page. The cross-check result is that it is defined directly by CIBJO and also appears in the GB/T annex. Kyanite also has an IMA Mineral List entry, registered as Kyanite Al2OSiO4 A 1967 s.p., cross-checked against the RRUFF/IMA master mineral list and marked as public domain data.
This table scrolls sideways on narrow screens.
| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Kyanite | 7.2.1.125 | Blue, blue-green, green, yellow to red, colourless; transparent, translucent | Defined directly by CIBJO; also present in the GB/T annex. |
| Kyanite | IMA Mineral List entry | Kyanite Al2OSiO4 A 1967 s.p. | Cross-checked against the RRUFF/IMA master mineral list (public domain data). |
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.
- RRUFF Project, in partnership with the IMA – International Mineralogical Association. IMA Mineral List.
- Geological Survey of Japan, AIST (Japan). Mineral specimen m16593: Kyanite.
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.
This table scrolls sideways on narrow screens.
| Page | Content | Status |
|---|---|---|
| Browsing family | Other silicate minerals | Live |
| Treatments recorded for this material | Dyed, Filled / Fracture-filled | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Kyanite 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.