On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Mineral / gemstone variety · Natural identity; treatment status unknown
Cat’s-eye
An effect variety name listed in GB/T 16552—2017 Table A.1. Clause 5.3.1 states that only chrysoberyl cat’s-eye may be called simply "Cat’s-eye". 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 Cat’s-eye forms and what gives its colourFormation setting, process and timescale; where its colour and optical effects come from, each finding graded and sourced
- How to identify Cat’s-eyeHow far lab testing can go
- Treatments and enhancements of Cat’s-eye1 registered treatments: status, stability, how common they are and identification leads
- Hardness, density and refractive index of Cat’s-eyeEach value with its source and check date
- Cat’s-eye 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 Cat’s-eyeThe listing name to use; what must be disclosed before sale
- Standard clauses that define Cat’s-eyeWhich 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
'Cat's-eye' first names an optical effect (chatoyancy): a narrow bright band on a cabochon-cut gemstone that shifts as the stone turns, produced when parallel needle inclusions or fibrous textures scatter light that the cabochon surface focuses like a convex lens. Used as a variety-restricted name, standard practice requires a chatoyant stone to be given its correct mineral name with the prefix or suffix 'cat's-eye' (e.g. cat's-eye tourmaline, tourmaline cat's-eye); where the mineral species is unspecified, 'cat's-eye' defaults to cat's-eye chrysoberyl (BeAl2O4), also called cymophane. In chrysoberyl the needles are almost entirely rutile, thought to arise through exsolution-precipitation of titanium that was initially held in solution within the structure — that is, as the chrysoberyl host cools after forming.
Scope: Applies to the mechanism and naming conventions of the cat's-eye effect (with chrysoberyl cat's-eye as the default "cat's-eye"); does not cover asterism, nor does it make material determinations for commercial "cat's-eyes" whose mineral species is not specified.
Sources G&G Summer 2025 · CIBJO Gemstone Book 2022
Where it forms
Be-bearing systems (such as granitic pegmatites) — the parent setting of cat's-eye chrysoberyl.
Sources G&G Summer 2025
A broad needle/fibre-inclusion setting: any gemstone with parallel needle inclusions or fibrous textures can show chatoyancy, depending on the species.
Sources G&G Summer 2025
How it forms, step by step
The host mineral crystallises and the relevant trace element enters the lattice (titanium in chrysoberyl).
On cooling, oriented needle inclusions precipitate (rutile needles in chrysoberyl, aligned along specific crystallographic directions).
The parallel needles scatter light, and a cabochon cut focuses it into a bright line that moves as the stone rotates — the cat's-eye.
Link to appearance
The cat's-eye line is formed by selective scattering from parallel needle/fibre inclusions focused by the cabochon; denser needles generally give a sharper eye, and the line runs perpendicular to the needle direction.
Sources G&G Summer 2025 · CIBJO Gemstone Book 2022
Timescale
The cited sources give no absolute timescale for the cat's-eye effect itself; chrysoberyl's needle inclusions exsolve on cooling after the host crystallises.
Sources G&G Summer 2025 · CIBJO Gemstone Book 2022
Related base materials
- Chrysoberyl (BeAl2O4): Default mineral species: when no mineral species is specified, 'cat's-eye' refers specifically to chrysoberyl cat's-eye (cymophane)
- (Any gemstone exhibiting chatoyancy): More broadly, 'cat's-eye' is the name of an optical effect; cat's-eyes of other minerals must be prefixed with the mineral species name (e.g. tourmaline cat's-eye)
Supporting findings
In cat's-eye chrysoberyl the needles are almost entirely rutile; they are thought to arise through exsolution-precipitation of titanium that was initially held in solution within the chrysoberyl structure, so they develop as the host cools after crystallising.
Evidence grade AScope: Concerns chrysoberyl's inclusion genesis; the rare exception is ilmenite needles in a four-rayed star chrysoberyl from Sri Lanka.
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Asia
- Sri LankaOne of the two largest suppliers in 1988, though output had dropped sharply
Sources Gems & Gemology Spring 1988
Europe
- Ural Mountains, RussiaHistoric source; classic deposits likely exhausted
Sources Gems & Gemology Spring 1988
South America
- Santana and Americana valleys near Padre Paraíso, Minas Gerais, Brazil1988: Minas Gerais and Sri Lanka the two largest suppliers; ≥95% of Minas Gerais output from these valleys
Sources Gems & Gemology Spring 1988
These are localities recorded by authoritative sources, not an origin finding for any individual piece. The CIBJO Gemstone Book (2022, §4.2.3) says a place of origin names where a gem was mined or harvested, is a matter of opinion, does not imply a level of quality, and that cutting, processing or exporting centres must not be used to imply origin. See how far testing can go on this page, the origin determination guide and the overview of recorded localities.
Causes of colour and optical effects
A cat's-eye effect arises when light scattered by parallel needle inclusions or fibrous textures is concentrated by a cabochon's domed surface into a narrow bright band; that band shifts position as the stone turns relative to the light source.
Evidence grade AScope: Describes the cat's-eye (one-dimensional needle/fibre) mechanism, not asterism; cut and inclusion density affect the effect.
Sources G&G Summer 2025 · CIBJO Gemstone Book 2022
Other research findings
Standard practice requires a chatoyant stone to be named with the correct mineral species plus the prefix/suffix 'cat's-eye' (e.g. cat's-eye tourmaline); when the species is not specified, 'cat's-eye' refers by default to cat's-eye chrysoberyl (cymophane) — matching the Chinese GB/T convention in which 'cat's-eye' denotes chrysoberyl cat's-eye while others must be labelled 'xx cat's-eye'.
Evidence grade AScope: The naming convention is supported by CIBJO and the GIA review; the GB/T text has not been obtained (see Limitations for the Chinese-standard correspondence).
Sources G&G Summer 2025 · CIBJO Gemstone Book 2022
Overall, cat's-eye is a variety-restricted name for the optical effect (chatoyancy): parallel needle/fibre inclusions scatter light that a cabochon focuses into a band; the standard takes chrysoberyl cat's-eye as the default 'cat's-eye', with other minerals labelled 'xx cat's-eye'.
Evidence grade BScope: A multi-source summary; a given specimen's species and cause require case-by-case identification.
Sources G&G Summer 2025 · CIBJO Gemstone Book 2022
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The Chinese GB/T (gemstone nomenclature) text has not yet been obtained; the correspondence that 'cat's-eye' denotes chrysoberyl cat's-eye while others are labelled 'xx cat's-eye' is supported by CIBJO's naming convention and the GIA review as an inferred mapping at the level of naming practice, and the GB/T text is authoritative.
- 'Cat's-eye' is a variety-restricted name for an optical effect, not an independent mineral species; an unspecified 'cat's-eye' on the market must be identified as chrysoberyl before the plain term is used.
- This record excludes the asterism mechanism and gives no absolute timescale for any particular cat's-eye effect.
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
- Cat's-eye (the mineral name must be added)
GB/T 16552—2017 5.3.1 · IMA Mineral List 2026-07 “Chrysoberyl”
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
Cat’s-eye is Chatoyancy optical effect (GB/T formal name for chrysoberyl cat’s-eye); use "Cat's-eye (the mineral name must be added)" for listings, and disclose any known treatments.
Evidence
- GB/T · 5.3.1
What this means for you
Before buying, check the recommended listing name "Cat's-eye (the mineral name must be added)" 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
Treatments and identification leads
Registered treatmentsThe treatment registered for Cat’s-eye is irradiation. Values not givenIts status is irradiated or dyed; stability and market prevalence are both registered as "—", meaning the cited source gives no value, not "none". Identification cluesThe identification lead for irradiation is that irradiation can improve the chatoyancy and colour, and it is difficult to detect. The source is GB/T 16553—2017.
This table scrolls sideways on narrow screens.
| 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
The name register below lists one name for Cat’s-eye in a non-Latin script: 1 with no restriction recorded on use as a name.
Standard and listing namesThe Chinese formal name for Cat’s-eye comes from GB/T 16552—2017 Table A.1; the suggested listing name is Cat’s-eye (the mineral name must be added), and the trade name/synonym is cat’s-eye chrysoberyl. Sub-names and unacceptable namesIn the name register, cat’s-eye chrysoberyl is a subordinate name at variety/sub-type level and serves only as a search candidate; the related high-risk name is cat’s-eye stone. Names in four languagesNames are given in Simplified Chinese, Traditional Chinese, English (Cat’s-eye) and Japanese (a katakana transliteration); the GSJ (Japan) formal name is shown as that katakana form, but Japan's GSJ wording for it is not yet verified by this site, and what is shown is the entry's own Japanese name. Trade and mineralogical namesThe mineralogical name is registered as Chatoyancy optical effect (the GB/T formal name for chrysoberyl cat’s-eye). Institution usageOn authority wording, the FTC text on file has no wording for Cat’s-eye (checked), and GIA, CIBJO 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) | ||||
| 猫眼金绿宝石Simplified Chinese | narrower name (variety or subtype) | search candidate only | no restriction recorded | editorial ruling (no clause cited); Note: Related high-risk name “Cat's Eye”. |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- キャッツアイ (not yet checked for this body — the entry's own Japanese name is shown)
- Chinese formal name
- 猫眼 (GB/T 16552—2017 Table A.1)
- Mineralogical name
- Chatoyancy optical effect (GB/T formal name for chrysoberyl cat’s-eye)
Four-language names
- 简体中文
- 猫眼
- 繁體中文
- 貓眼
- English
- Cat’s-eye
- 日本語
- キャッツアイ
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural inorganic gem materials
- Browsing family
- Oxide minerals
- Identity tier
- Mineral / gemstone variety
- Mineral chemical class
- Oxides / hydroxides
- Construction or treatment status
- Natural identity; treatment status unknown
Treatments listed by standards
In GB/T 16552—2017 Annex B, Table B.1, Cat’s-eye is listed as its own entry; the treatment recorded there is irradiation, with the effect recorded as improving the eye, colour and other aspects of appearance, and the category treatment. The notes to Table B.1 and the definitions of each treatment category are on this site's Gem treatments page.
GB/T 16552-2017, Annex B, Table B.1
Table B.1, row “Cat’s-eye” (p.14):
This table scrolls sideways on narrow screens.
| Method | Effect | Category |
|---|---|---|
| Irradiation | Improves the eye line, 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.
What it is and how it's identified
The material facts registered for Cat’s-eye under GB/T 16553—2017 are as follows. Composition is BeAl2O4 and may contain elements such as Fe and Cr; the structure is crystalline, orthorhombic, with a tabular or granular habit, and it can form pseudo-hexagonal trillings. Mohs hardness is 8–8.5 and cleavage is three imperfect directions; this site notes that hardness alone is not enough to judge durability. Density is 3.71–3.75 g/cm³, derived from the cited clause value of 3.73 with a tolerance of ±0.02; refractive index is 1.74–1.759, derived from the clause value of 1.746–1.755 with a tolerance of +0.004/−0.006, and this site notes that the clause has finer sub-ranges and the overall value is registered; birefringence is 0.008–0.01. Optical character is anisotropic, biaxial positive. Among optical effects, chatoyancy and colour change can be seen, and the UV-visible spectrum shows a strong absorption band at 445nm. Untreated Cat’s-eye has a vitreous lustre.
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
Cat’s-eye — composition (chemistry): BeAl2O4, 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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Structure
Cat’s-eye — 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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Cat’s-eye — structure (crystal system): orthorhombic
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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Cat’s-eye — structure (crystal habit): tabular or granular; pseudo-hexagonal trilling twins
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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Durability
Cat’s-eye — Mohs hardness: 8–8.5
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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Cat’s-eye — cleavage: imperfect in three directions
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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Physical properties
Cat’s-eye — density: 3.71–3.75 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 3.73, with a stated tolerance of ±0.02. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Optical
Cat’s-eye — optic character: biaxial, optically positive (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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Cat’s-eye — refractive index: 1.74–1.759
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 1.746–1.755, with a stated tolerance of +0.004 / -0.006. The range shown here is worked out from that.
- General note
- the clause has finer ranges
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Cat’s-eye — birefringence: 0.008–0.01
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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Cat’s-eye — pleochroism: weak trichroism: yellow, yellow-green and orange.
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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Cat’s-eye — fluorescence (overall): none; alexandrite cat’s eye: weak to moderate, red.
GB/T 16553—2017
UV fluorescenceredweak–moderate, alexandrite cat’s eyeDots 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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Cat’s-eye — spectrum (UV-visible): 445 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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Cat’s-eye — spectrum (infrared): Chrysoberyl's Be-O and Al-O lattice vibrations produce its diagnostic bands in the mid-IR.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-22
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.5 (locator checked 2026-09-22)
- Fact checked on
- 2026-09-22
Cat’s-eye — 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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Cat’s-eye — optical effect (colour change): 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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Cat’s-eye — magnification: "silk" inclusions, gas-liquid inclusions, fingerprint-like inclusions, negative crystals.
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): §5.1.5 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Cat’s-eye — body colour: yellow to yellow-green, grey-green, brown to brownish yellow and similar colours; the rare alexandrite cat's-eye comes in blue-green and purplish brown.
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 Chrysoberyl, Iolite, Zoisite and other variety clauses also name yellow or a yellowish colour.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.5 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
- CIBJO definitions
- chatoyancy, colour change
Quality factors
Cat’s-eye — 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): §5.1.5 (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): 1.749 / 3.73; Closest values: 1Cobalt Spinel 1.723 / 3.63, 2Grossular 1.745 / 3.9, 3Malachite 1.782 / 3.67, 4Rhodolite 1.755 / 3.9, 5Benitoite 1.78 / 3.65
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
When Cat’s-eye has been irradiated, the identification lead is that irradiation can improve the cat's-eye effect and the colour, and is difficult to detect. The treatment status for irradiation is irradiated or dyed, applying to irradiation; the identification lead is cited from GB/T 16553—2017 Gems — Testing, which can only be used as a reference for Cat’s-eye and does not govern it directly. The CIBJO laboratory protocol covers Cat’s-eye under "Chrysoberyl"; for identification see the Chrysoberyl entry, and the list of required methods is on the laboratory testing page.
The CIBJO laboratory protocol covers Cat’s-eye under “Chrysoberyl” (§6.1.18): see identification on the Chrysoberyl entry; the required tests are listed on the CIBJO laboratory protocol table for Chrysoberyl.
How far testing can go
Cat’s-eye that has undergone irradiation can be identified by the following features: Irradiation can improve the cat's eye effect and the colour; 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): §5.1.5 (irradiation) (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.
Clause-level definitions
At clause level, Cat’s-eye is registered under the term Cat’s-eye, based on GB/T 16552—2017 Annex A. GB/T 16552—2017 gives no spelled-out definition, only a pointer to the full description elsewhere in the standard. The cross-check shows that GB/T lists Cat’s-eye directly, while no standalone CIBJO entry under the same name was found.
This table scrolls sideways on narrow screens.
| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Cat’s-eye | GB/T 16552-2017 Annex A | For the full description, see §5.3.1 in GB/T 16552—2017. | Listed directly by GB/T; CIBJO carries no standalone entry under the same name. |
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 | Oxide 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 Cat’s-eye 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.