On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Mineral species · Natural identity; treatment status unknown
Euclase
A silicate mineral species listed in GB/T 16552-2017 Appendix A.1; Euclase has pronounced cleavage and brittleness, so a caution about durability in wear is needed. 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 Euclase forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify EuclaseHow far lab testing can go and whether a synthetic exists
- Treatments and enhancements of Euclase1 registered treatments: status, stability, how common they are and identification leads
- Caring for and wearing EuclaseCleaning, heat, chemicals and light, as the cited sources give them; durability indicators and wearing advice
- Hardness, density and refractive index of EuclaseEach value with its source and check date
- Euclase 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 EuclaseWhere the name comes from
- Listing and disclosing EuclaseThe listing name to use; what must be disclosed before sale
- Standard clauses that define EuclaseWhich 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
Euclase is a beryllium aluminium hydroxide silicate species with the ideal formula BeAlSiO4(OH), crystallising in the monoclinic system. It forms mainly as a product of the decomposition of beryl in pegmatites and also in low-temperature alpine veins, so it is a beryllium-bearing material crystallising in Be-rich pegmatitic and low-temperature hydrothermal vein settings.
Scope: Applies to the genesis and occurrence of natural euclase as a beryllium aluminium silicate mineral species; does not cover synthetics or artificial imitations.
Sources Handbook of Mineralogy
Where it forms
Be-rich pegmatites (at sites of beryl decomposition) and low-temperature alpine veins
Sources Handbook of Mineralogy
Associated minerals: feldspar, quartz, topaz, beryl, mica, calcite, ankerite, chlorite
Sources Handbook of Mineralogy
How it forms, step by step
Beryllium-bearing minerals such as beryl crystallise in a Be-rich pegmatite.
Sources Handbook of Mineralogy
Later fluids decompose the beryl, releasing beryllium, aluminium and silicon.
Sources Handbook of Mineralogy
Euclase crystals precipitate in the pegmatite or in low-temperature alpine veins.
Sources Handbook of Mineralogy
Euclase occurs with feldspar, quartz, topaz, beryl, mica and other minerals.
Sources Handbook of Mineralogy
Link to appearance
Euclase forms euhedral prismatic crystals (up to 12 cm) that are morphologically complex; colours range from colourless and white to pale-to-deep yellowish green, greenish blue and pale-to-deep blue, rarely mottled. Its perfect cleavage yields flat fracture surfaces, and the name alludes to the Greek for 'easily fractured'. The source states no colour mechanism.
Sources Handbook of Mineralogy
Timescale
The source states no absolute geological timescale for euclase formation.
Sources Handbook of Mineralogy
Supporting findings
Euclase is the product of the decomposition of beryl in pegmatites, and it also occurs in low-temperature alpine veins.
Evidence grade BScope: Describes the natural formation mode of euclase.
Sources Handbook of Mineralogy
Euclase is commonly associated with feldspar, quartz, topaz, beryl, mica, calcite, ankerite and chlorite.
Evidence grade BScope: Describes the association; no single locality is specified.
Sources Handbook of Mineralogy
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Africa
- Andilamena, Madagascar
Sources Mindat: Euclase
- Mikese, Morogoro, Tanzania
Sources Handbook of Mineralogy · Mindat: Euclase
- Klein Spitzkoppe, Erongo, Namibia
Sources Mindat: Euclase
Asia
- Ratnapura, Sri Lanka
Sources Mindat: Euclase
- Mogok area, Myanmar
Sources Mindat: Euclase
Europe
- Sanarka River, Southern Urals, Russia
Sources Handbook of Mineralogy
North America
- Mount Antero area, Colorado, United States
Sources Mindat: Euclase
South America
- Ouro Preto, Minas Gerais, Brazil
Sources Mindat: Euclase
- Minas Gerais, Brazil
Sources Handbook of Mineralogy
- Gachalá, Cundinamarca, ColombiaLarge crystals
Sources Mindat: Euclase · 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.
Where the name comes from
Euclase takes its English name from Greek words for 'easily' and 'fracture', referring to its perfect cleavage.
Evidence grade BScope: Etymology explains the origin of the name only; it does not establish the material's composition, locality, naturalness, or treatment.
Sources Handbook of Mineralogy
Other research findings
Euclase is a beryllium aluminium hydroxide silicate species with ideal formula BeAlSiO4(OH), crystallising in the monoclinic system.
Evidence grade BScope: Species-level composition and crystal-system fact.
Sources Handbook of Mineralogy
Euclase colours include colorless, white, greenish blue, pale blue to deep blue, and pale green through deep yellowish green; mottled stones are rare.
Evidence grade BScope: Describes the colour range only; no colour mechanism is implied.
Sources Handbook of Mineralogy
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The source is a mineralogical data sheet and gives no absolute geological timescale for euclase formation.
- The source gives no colour mechanism or specific P-T conditions for euclase.
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
- Euclase
GB/T 16552—2017 Table A.1 “Euclase” · IMA Mineral List 2026-07 “Euclase”
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Irradiated
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
Euclase is Euclase; use "Euclase" for listings, and disclose any known treatments.
Evidence
- GB/T · Table A.1, row 蓝柱石 (Euclase)
What this means for you
Before buying, check the recommended listing name "Euclase" 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
Euclase — 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, Euclase, p.51; §6.2 j (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
Euclase — care (wear): cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code b
- Treatment state
- any treatment state
Source & check 2026-09-25
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, Euclase, p.51; §6.2 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
CleaningEuclase must not be cleaned ultrasonically; the CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) gives this cleaning advice irrespective of treatment status. WearThe same source states that Euclase cleaves or fractures easily and should be worn with care, and this wearing advice likewise applies irrespective of treatment status.
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| Question | Matching entries |
|---|---|
| Can it go in an ultrasonic or steam cleaner? | care (cleaning) |
| Wearing limits (knocks, settings) | cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care |
Durability and wearing
Toughness
Brittle
Treatments and identification leads
Values not givenThe treatment registered for Euclase is irradiation, with the status irradiated or dyed; for the stability and prevalence of irradiation the cited source gives no value, shown in the original as “—”, which does not mean “none”. Identification cluesThe identification lead for irradiation is that colourless material turns blue or light green when irradiated, and this is hard to detect. The related identification conclusion for irradiation is cited from GB/T 16553—2017, whose cited clause serves only as a reference for euclase and does not govern it directly. SyntheticsThe registered entries for euclase also state that there is no synthetic euclase on the market.
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| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| irradiationStatus: irradiated or dyed | — | — | Treatment | — | See identification leads |
Where each treatment acts (schematics): Irradiated
“—” 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
Standard and listing namesThe Chinese formal name of Euclase comes from GB/T 16552—2017 Table A.1, the mineralogical name is Euclase, and the suggested listing name is Euclase. Names in four languagesFour-language names are given in Simplified Chinese, Traditional Chinese, English (Euclase) and Japanese; for Japan's GSJ, the entry has its own Japanese name, and the wording of Japan's GSJ for this name is not yet verified by this site. Institution usageOn authority wording, CIBJO records Euclase (CIBJO Gemmological Laboratories Book 2024); the FTC text on file has no wording for Euclase (checked); GIA and Gem-A are unchecked, and bodies without a recorded wording show the entry's own English name, which does not represent their position.
- GSJ (Japan) formal name
- ユークレース／藍柱石 (not yet checked for this body — the entry's own Japanese name is shown)
- Chinese formal name
- 蓝柱石 (GB/T 16552—2017 Table A.1)
- Mineralogical name
- Euclase
Four-language names
- 简体中文
- 蓝柱石
- 繁體中文
- 藍柱石
- English
- Euclase
- 日本語
- ユークレース／藍柱石
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
For Euclase, the "Euclase" row of GB/T 16552—2017 Annex B, Table B.1 lists irradiation, with the effect of changing colour and the category treatment. What Table B.1 is, and how its grades are defined, are on the Gem treatments page.
GB/T 16552-2017, Annex B, Table B.1
Table B.1, row “Euclase” (p.15):
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| Method | Effect | Category |
|---|---|---|
| Irradiation | Changes colour | 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.
What it is and how it's identified
The registered material facts for Euclase are: composition BeAlSiO4(OH), which may contain Fe, Cr and other elements, with the phase euclase; the structure is crystalline and monoclinic, with a short prismatic crystal habit. Mohs hardness is 7–8, with one direction of perfect cleavage; a further note states that hardness alone is not enough to judge durability. Density is 3–3.12 g/cm³; the cited clause gives 3.08 with a tolerance of +0.04/−0.08, from which the limits are derived. The optic character is anisotropic, biaxial negative; refractive index is 1.65–1.677, the cited clause giving 1.652–1.671 with a tolerance of +0.006/−0.002, from which the limits are derived; birefringence is 0.019–0.02. For untreated Euclase, pleochroism varies with colour: blue stones show bluish grey and light blue, green stones greyish green and green; the lustre is vitreous.
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
Euclase — nomenclature status: IMA status G: grandfathered (described before the IMA existed, and generally regarded as a valid species).
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Euclase — composition (chemistry): BeAlSiO4 (OH), elements such as Fe and Cr 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): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Euclase — composition (phase): euclase
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Structure
Euclase — 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): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Euclase — structure (crystal system): monoclinic
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): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Euclase — structure (crystal habit): short-columnar
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): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Durability
Euclase — 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): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Euclase — cleavage: perfect in one direction
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Physical properties
Euclase — density: 3–3.12 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 3.08, with a stated tolerance of +0.04 / -0.08. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Optical
Euclase — 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): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Euclase — refractive index: 1.65–1.677
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 1.652–1.671, with a stated tolerance of +0.006 / -0.002. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Euclase — birefringence: 0.019–0.02
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): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Euclase — transparency: transparent.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Euclase — pleochroism: varies with colour: blue shows blue-grey and light blue; green shows grey-green and green.
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): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Euclase — fluorescence (overall): none to weak
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): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Euclase — spectrum (UV-visible): 468 nm absorption band; 455 nm absorption band; absorption in the green and red regions.
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): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Euclase — spectrum (infrared): The mid-IR spectrum carries euclase'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): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Euclase — magnification: gas-liquid inclusions, mineral inclusions, growth striations, color band, 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): §5.1.42 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
body colour2 sources compared
Euclase — body colour: colourless, yellowish to bluish green, (usually light) blue to greenish blue.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Kornerupine, Kyanite, Brazilianite and other entries also name colourless.
- General note
- colour alone is not identity
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Euclase — body colour: colorless, or blue-green, blue, green-blue and similar colours with a yellowish tinge, generally pale.
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 Kornerupine, Celestite / Celestine, Brazilianite and other variety clauses also name colourless.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.42 (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
The two entries broadly agree: colourless, yellowish to bluish green and blue-green, and blue to greenish blue; both mention light tones (GB/T 16553—2017 says the colour is usually light, the CIBJO Gemmological Laboratories Book that the blue is usually light).
Quality factors
Euclase — 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): §5.1.42 (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): 1.663 / 3.06; Closest values: 1Phenakite 1.673 / 2.95, 2Datolite 1.646 / 2.95, 3Sillimanite 1.668 / 3.21, 4Danburite 1.633 / 3, 5Andalusite 1.639 / 3.17
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 identification lead for irradiated Euclase is that colourless Euclase turns blue or pale green on irradiation, and this is hard to detect. The lead applies to Euclase whose treatment state is irradiated or dyed and comes from GB/T 16553—2017, which can be followed for Euclase as a reference only and does not govern it directly. According to the CIBJO Blue Book — Official Gemstone Book (2022), no synthetic Euclase is available on the market.
How far testing can go
Euclase that has undergone irradiation can be identified by the following features: Irradiating colourless material produces blue or pale green; hard 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): §5.1.42 (irradiation) (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Euclase — 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
Euclase has a direct definition in the CIBJO Gemmological Laboratories Book 2024 under the entry Euclase; the definition gives the mineral species as euclase, IMA status G, with the CIBJO wording quoted in full under Clause-level definitions on this page, and the cross-check result is: defined directly by CIBJO, and also appears in the GB/T annex. Under the IMA Mineral List entry, Euclase is recorded as Euclase BeAlSiO4(OH) G 1792, cross-checked against the RRUFF/IMA master mineral list (public domain data).
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| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Euclase | 7.2.1.85 | colourless, yellowish to bluish green, (usually light) blue to greenish blue; transparent | Defined directly by CIBJO; also present in the GB/T annex. |
| Euclase | IMA Mineral List entry | Euclase BeAlSiO4(OH) G 1792 | 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). Museum mineral specimens, browse by classification.
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 | Irradiated | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Euclase 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.