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Artificial products / Manufactured products · Artificial product type · Man-made glass
Man-made Fibre-optic Cat’s-eye Glass
Also known asCat eye glass
Man-made fibre-optic glass that shows a cat's-eye effect. It is not natural cat's-eye Chrysoberyl and must not be labelled "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 Man-made Fibre-optic Cat’s-eye Glass forms and what gives its colourFormation setting, process and timescale; where its colour and optical effects come from, each finding graded and sourced
- Hardness, density and refractive index of Man-made Fibre-optic Cat’s-eye GlassEach value with its source and check date
- Man-made Fibre-optic Cat’s-eye Glass in English, Chinese and Japanese; national standard namesNames in four languages, the GB/T standard name and the suggested listing name, names in national standards; and: Has any of GIA, FTC, CIBJO or Gem-A put a name for it on record here?
- Listing and disclosing Man-made Fibre-optic Cat’s-eye GlassThe listing name to use; what must be disclosed before sale
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
'Man-made cat's-eye' is a market name for a man-made product with a cat's-eye-like appearance. The cited authoritative sources (CIBJO Gemstone Book 2022 and the relevant GIA pages) do not define the specific material or process under this name, so on present authority it cannot be confirmed whether it is made of fibre-optic glass (or another material). GIA states only generally that glass can be made to look like phenomenal gems such as tiger's eye and opal, which is not an identification of this item. Under CIBJO naming principles such an artificial product should be described by the name of its constituent material or as 'imitation + imitated material name'. This record therefore gives an identity boundary only: it is a market name whose material is pending testing.
Scope: Applies only to defining "ren zao mao yan shi" (man-made cat's-eye) as a man-made/market name of undetermined material; not to be used to assert its material composition or manufacturing process.
Sources CIBJO Gemstone Book 2022 · GIA Introduction to Imitation Gems
Where it forms
Natural occurrence environment does not apply: the natural setting of the material under this name is moot because the material itself is not established by authority.
Sources CIBJO Gemstone Book 2022
Manufacturing conditions undefined: the cited authorities do not describe the material or process behind 'man-made cat's-eye'.
Sources CIBJO Gemstone Book 2022 · GIA Introduction to Imitation Gems
How it forms, step by step
(Unknown) The cited authorities do not define what material 'man-made cat's-eye' is made from (it cannot on this basis be asserted to be fibre-optic glass).
Sources CIBJO Gemstone Book 2022
(Unknown) The cited authorities give no manufacturing or assembly process for it.
Sources CIBJO Gemstone Book 2022
(Advisory) Per CIBJO naming principles, its material must first be determined, then disclosed truthfully by material name or as 'imitation + target name'.
Sources CIBJO Gemstone Book 2022
Link to appearance
'Man-made cat's-eye' is used to imitate the light-band appearance of natural cat's-eye (e.g. chrysoberyl cat's-eye). GIA states only generally that glass can be made to look like phenomenal gems such as tiger's eye and opal, showing that imitating phenomenal gems with man-made materials occurs, but this does not establish that this item is glass. Appearance similarity must be tested before a material can be determined.
Sources CIBJO Gemstone Book 2022 · GIA Introduction to Imitation Gems
Timescale
The cited authorities give no timescale for this name or material.
Sources CIBJO Gemstone Book 2022
Causes of colour and optical effects
Natural or man-made, chatoyancy requires a set of mutually parallel fibrous or needle-like structures inside the material: light these structures reflect and scatter is gathered by a cabochon into a bright band set at right angles to their length. In a man-made 'cat's-eye' those parallel structures are created artificially (for instance oriented fibres or glass filaments), but the cited sources do not document the exact process, so only the general optical requirement is stated here; the specific material and method are not inferred from appearance.
Evidence grade AScope: States only the general geometric-optics requirement for a cat's-eye; the material and process of a man-made product lack source support and are not used here as an identification conclusion.
Other research findings
Under CIBJO an artificial product used in jewellery must be described by the name of the material it is composed of or as 'imitation + imitated material name'; a trade name carrying no material information (such as 'man-made cat's-eye') does not meet this requirement.
Evidence grade AScope: A naming rule used to note the compliance issue; it does not determine the material.
Sources CIBJO Gemstone Book 2022
CIBJO defines 'artificial stones' as artificial products used in jewellery or objets d'art that have no natural counterparts; even if 'man-made cat's-eye' belongs to this class, the name alone still does not state its manufacturing material.
Evidence grade AScope: A category definition stated conditionally; not an identification of this item.
Sources CIBJO Gemstone Book 2022
In CIBJO's terms, an imitation copies how a natural material looks while lacking that material's chemistry, physical properties and structure; accordingly, from the appearance name 'man-made cat's-eye' alone neither its material can be determined nor can it be asserted to be fibre-optic glass.
Evidence grade AScope: Establishes that an appearance name is insufficient; gives no material conclusion.
Sources CIBJO Gemstone Book 2022
GIA states that glass can be made to look like phenomenal gems such as tiger's eye and opal; this shows that imitating phenomenal gems with man-made materials occurs, but it is not an identification of this item.
Evidence grade AScope: A general source statement about imitation practice; it does not identify this item's material.
Sources GIA Introduction to Imitation Gems
Limits of this research
- Research status: Only partial material-specific findings found; gaps are stated as gaps
- The cited authorities do not define the material attribution or manufacturing process of 'man-made cat's-eye', and it cannot on this basis be asserted to be fibre-optic glass; the actual material requires testing.
- Common market practice (e.g. manufacture from fibre-optic glass) is not an identification and is not treated as a conclusion here.
- 'Man-made cat's-eye' may denote different materials in different markets and must be tested per item.
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
- Man-made fibre-optic cat's-eye glass
GB/T 16552—2017 5.1.1 c), 5.1.3.2 a), 5.2.1 b)
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
"Man-made Fibre-optic Cat’s-eye Glass" is a market name rather than a mineral species name; before using it, verify: Not a mineral: man-made or non-mineral material.
What this means for you
Before buying, check the recommended listing name "Man-made fibre-optic cat's-eye glass" 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
- Not a mineral: man-made or non-mineral material.
- Suggested listing name
- Man-made fibre-optic cat's-eye glass
VerifyNames, standards, technical facts, clauses and sources
Names
Besides Man-made Fibre-optic Cat’s-eye Glass, the name register records "Cat eye glass", for which no restriction on use as a name is recorded.
Standard and listing namesUnder GB/T 16552—2017, the name Man-made Fibre-optic Cat’s-eye Glass is not listed in the original, and the naming counterpart is glass; the suggested listing name is man-made cat's-eye glass. Trade and mineralogical namesCat eye glass is a trade name/synonym, registered as an English market name by this site's own ruling (without a clause). Take care with the related high-risk Chinese name for cat's-eye stone: Cat's eye can also refer to natural cat's-eye material, so when used as a name it must state man-made. The mineralogical name is written Man-made fiber-optic glass. Names in four languagesFour-language names are given in Simplified Chinese, Traditional Chinese, English (Man-made Fibre-optic Cat’s-eye Glass) and Japanese. Institution usageOn authority wording, the wording of GIA, FTC, CIBJO and Gem-A for this name is not yet verified by this site; the page shows the entry's own English name, Man-made Fibre-optic Cat’s-eye Glass, which does not represent the position of any of them. Japanese namesFor the formal name of 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. National standard namesGermany (RAL) writes Glas-Katzenauge (Imitation), and the EU writes Glass Imitation Cat's-eye.
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) | ||||
| Cat eye glassEnglish | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited); Note: Related high-risk name “Cat's Eye”: cat's eye can also mean natural chatoyant material, so the man-made nature must be stated. |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- キャッツアイガラス (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)
- 玻璃 (GB/T 16552—2017 §5.1.3.2 a))
- Mineralogical name
- Man-made fiber-optic glass
- Trade names and synonyms
- Cat eye glass (market name)
Four-language names
- 简体中文
- 人造猫眼石
- 繁體中文
- 人造貓眼石
- English
- Man-made Fibre-optic Cat’s-eye Glass
- 日本語
- キャッツアイガラス
National and regional formal names
- Germany (RAL)
- Glas-Katzenauge (Imitation)
- European Union
- Glass Imitation Cat's-eye
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Artificial products / Manufactured products
- Material domain
- Artificial products / Manufactured products
- Browsing family
- Man-made glass products
- Identity tier
- Artificial product type
- Mineral chemical class
- Not applicable
- Construction or treatment status
- Man-made glass
What it is and how it's identified
Most of the registered material facts for Man-made Fibre-optic Cat’s-eye Glass take GB/T 16553—2017 values for manufactured glass as a whole class; they are not measurements of Man-made Fibre-optic Cat’s-eye Glass itself. For manufactured glass (the whole class): structure (overall) amorphous; Mohs hardness 5–6, a common typical value rather than an absolute limit; cleavage none; density 2.3–4.5 g/cm³, likewise a common typical value rather than an absolute limit; optic character isotropic, often with anomalous optical behaviour; refractive index 1.47–1.7, the registered value being the overall one although the clause has finer sub-ranges for refractive index; birefringence none; untreated, pleochroism none and the quality factor (lustre) vitreous. Optical effects also take values for manufactured glass (the whole class): play of colour, iridescence, chatoyancy, asterism, aventurescence, colour change and sheen are all visible. Chemical composition, luminescence, UV-visible spectrum, infrared spectrum and magnification are written for manufactured glass as a whole class on the Glass entry.
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”.
Chemical composition, luminescence, UV-visible spectrum, infrared spectrum, magnification: these whole-class features are given in the cited clause for manufactured glass (whole class), so they are not repeated on the Man-made Fibre-optic Cat’s-eye Glass page; see the material facts on the Glass entry.
Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of Man-made Fibre-optic Cat’s-eye Glass (how to read class-level values).
Structure
Man-made Fibre-optic Cat’s-eye Glass — structure (overall): amorphous (not crystalline)
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Durability
Man-made Fibre-optic Cat’s-eye Glass — Mohs hardness: 5–6
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
- manufactured glass (whole class)
- Qualification
The clause we cite gives this as a typical value. It is a common value, not an absolute limit.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Man-made Fibre-optic Cat’s-eye Glass — cleavage: none
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Physical properties
Man-made Fibre-optic Cat’s-eye Glass — density: 2.3–4.5 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
- Qualification
The clause we cite gives this as a typical value. It is a common value, not an absolute limit.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Optical
Man-made Fibre-optic Cat’s-eye Glass — optic character: isotropic, commonly with anomalous optical behaviour
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Man-made Fibre-optic Cat’s-eye Glass — refractive index: 1.47–1.7
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
- General note
- the clause has finer ranges
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Man-made Fibre-optic Cat’s-eye Glass — birefringence: none
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Man-made Fibre-optic Cat’s-eye Glass — pleochroism: none
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Man-made Fibre-optic Cat’s-eye Glass — optical effect (play of colour): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Man-made Fibre-optic Cat’s-eye Glass — optical effect (iridescence): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Man-made Fibre-optic Cat’s-eye Glass — optical effect (chatoyancy): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Man-made Fibre-optic Cat’s-eye Glass — optical effect (asterism): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Man-made Fibre-optic Cat’s-eye Glass — optical effect (aventurescence): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Man-made Fibre-optic Cat’s-eye Glass — optical effect (colour change): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Man-made Fibre-optic Cat’s-eye Glass — optical effect (labradorescence): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
- CIBJO definitions
- play of colour, chatoyancy, asterism, aventurescence, colour change, labradorescence
Quality factors
Man-made Fibre-optic Cat’s-eye Glass — quality factor (lustre): vitreous
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- manufactured glass (whole class)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.4.20 (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): 1.585 / 3.4; Closest values: 1Hemimorphite 1.625 / 3.45, 2Imperial Topaz 1.623 / 3.53, 3Lazulite 1.627 / 3.12, 4Apatite 1.639 / 3.18, 5Synthetic Jadeite 1.66 / 3.34
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
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.
- Federal Trade Commission (United States). In the Loupe: Advertising Diamond, Gemstones and Pearls.
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 | Man-made glass products | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Man-made Fibre-optic Cat’s-eye Glass 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. The entry exists so that buyers and sellers can check naming, disclosure and material facts item by item.