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Artificial products / Manufactured products · Artificial product type · Imitation; record actual material
Imitation Opal
Also known asSimulated opal
A man-made product of glass, resin or similar materials that imitates the look of Opal. It does not meet the definition of Synthetic Opal and must not be called synthetic or lab-grown opal. 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 Imitation Opal 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 Imitation OpalIdentification points from the research literature
- Caring for and wearing Imitation OpalCleaning, heat, chemicals and light, as the cited sources give them
- Imitation Opal 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 Imitation OpalThe 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
Imitation opal is an artificial product that copies the look of opal using glass, resin/plastic, or natural materials selected by humans; it does not meet the definition of synthetic opal. GIA's study of play-of-colour Kyocera products showed that a material containing no water and not matching natural opal's composition should be classed as an opal simulant rather than a synthetic opal, even when it looks similar. Since opal has no well-defined chemistry or crystal structure, the line between synthetic opal and opal simulants is hard to draw. Although synthetic opal can be produced by the Stöber process, it is just as fragile as the natural material, so in fact opal simulants that are wholly or partly plastic are more common in the market.
Scope: Covers the definition of imitation/man-made opal; does not apply to the formation of natural opal, nor does it exhaustively list all commercial imitation recipes.
Sources G&G Fall 1987 · G&G Summer 2025 · GIA Opal
- Synthetic or Imitation? An Investigation of the Products of Kyocera Corporation That Show Play-Of-Color (Gems & Gemology, Fall 1987)
- Structures Behind the Spectacle: A Review of Optical Effects in Phenomenal Gemstones and Their Underlying Nanotextures
- GIA Gem Encyclopedia — Opal (Gemological Institute of America)
Where it forms
A man-made manufacturing environment (forming and coloring glass, resin, or plastic), not a natural geological one.
Sources GIA Opal
How it forms, step by step
Glass, resin, plastic, or other materials are formed to imitate opal’s appearance, simulating play-of-color or bodycolor as needed.
Sources GIA Opal
If the material contains no water and does not match natural opal’s composition, it is classed as a simulant rather than a synthetic opal.
The product is labelled and sold as an artificial product, never as natural or synthetic opal.
Sources GIA Opal
Link to appearance
Imitation opal aims at a similar appearance and may mimic play-of-color or bodycolor, but it lacks natural opal’s composition and structure, so it remains an artificial product.
Sources G&G Summer 2025
Timescale
The cited sources give no timescale for making imitation opal.
Sources G&G Summer 2025
Related base materials
- Opal: The material being imitated (the appearance of natural opal)
Causes of colour and optical effects
The play-of-colour-like appearance of an imitation opal is a structural colour, created by selective interference or diffraction of light at periodic or layered structures inside the material rather than by chemical pigments; such structural colours can also be produced artificially in media that are not natural opal (for example imitation glass or plastic, or a water-free Kyocera-type material). The visible effect alone therefore does not establish that the interior is a natural opal silica-sphere diffraction grating.
Evidence grade AScope: Stresses that similar appearance does not mean identical structure; a given imitation's material and process need separate testing, and the mechanism is not an identification conclusion for any single item.
How it is identified
An opal simulant may resemble natural opal in appearance while differing in composition—some imitations, for instance, contain no water and therefore do not match natural opal's makeup. Separating natural opal from a simulant requires laboratory testing of composition and structure, and the conclusion should be issued by an accredited body; no self-testing figures are offered here.
Evidence grade AScope: The composition/structure distinction requires professional laboratory testing; no self-service method is given.
Other research findings
Play-of-color Kyocera products, containing no water and not matching natural opal’s composition, were designated opal simulants rather than synthetic opal—so a similar appearance does not make a material synthetic.
Evidence grade AScope: A determination for specific Kyocera products, used here as a general illustration of the simulant-versus-synthetic boundary.
Since opal has neither a well-defined chemistry nor a well-defined crystal structure, it is hard to draw a clear boundary between synthetic opal and opal simulants, and the two terms must be used with care.
Evidence grade AScope: A terminology note from a GIA review; it flags the difficulty of definition without giving numeric criteria.
Since synthetic opal is just as fragile as the natural material, opal simulants that are wholly or partly plastic are in fact more common in the market.
Evidence grade BScope: Describes the relative commonness of plastic opal simulants on the market, not absolute production statistics.
Imitations can be fashioned from manmade materials or from natural ones selected by humans to pass as a particular gem; imitation opal is therefore an artificial product.
Evidence grade BScope: A category-level definition; it does not target any single imitation-opal material.
Sources GIA Opal
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The cited sources give only definitional generalities and the Kyocera case, with no compositional test data for specific imitation-opal materials.
- The literature explicitly notes that the boundary between imitation opal and synthetic opal is hard to define.
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
- Imitation Opal (state the material, e.g. glass or resin)
GB/T 16552—2017 5.2.1 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
"Imitation Opal" 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 "Imitation Opal (state the material, e.g. glass or resin)" 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
- Imitation Opal (state the material, e.g. glass or resin)
Care and wear
Care
Imitation Opal — care (wear): even light pressure from an ordinary sewing-needle tip leaves a dent in this plastic opal imitation; the authors note plastic imitations resist chipping but are soft, and reject the maker's claim that they scratch less readily than natural opal; the authors saw an outer coating, probably acrylic, applied to improve durability, already polished off in places.
Gems & Gemology 1989 (Koivula et al.)
- Treatment state
- any treatment state
Source & check 2026-10-06
- Source
- J.I. Koivula & R.C. Kammerling, “‘Opalite’: Plastic Imitation Opal with True Play-of-Color”, Gems & Gemology 25(1): 30–34 (1989): pp. 31, 33, body text (locator checked 2026-10-06)
- Fact checked on
- 2026-10-06
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
Each question links to the matching entries on this page; whether they answer it fully, go by the entry wording.
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VerifyNames, standards, technical facts, clauses and sources
Names
Besides Imitation Opal, the name register records "Simulated opal", for which no restriction on use as a name is recorded.
Standard and listing namesThe name formed for Imitation Opal under the GB/T 16552—2017 naming rules is imitation opal; the original GB/T 16552—2017 does not list imitation opal separately, and the basic name is opal. The suggested listing name is Imitation Opal (stating the material, such as glass or resin). Names in four languagesNames are given in four languages: Simplified Chinese, Traditional Chinese, English (Imitation Opal) and Japanese (two forms meaning imitation opal). For Japan's GSJ formal name, the entry's own Japanese name is shown, and Japan's GSJ wording for this name is not yet verified by this site. Institution usageOn authority wording, the FTC and CIBJO texts on file have no wording for Imitation Opal (checked), and GIA and Gem-A are unchecked; the entry's own English name is Imitation Opal, and bodies without a recorded wording show it, which does not represent their position. Trade and mineralogical namesThe trade name/synonym is Simulated opal, registered as a market name with no restriction recorded on its use as a name; related high-risk names include Synthetic, Composite and Imitation Opal. The mineralogical name describes glass, resin or other products with an opal-like appearance that do not meet the definition of synthetic opal.
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.
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| Name | Type | Matching | Use as a name | Basis |
|---|---|---|---|---|
| no restriction recorded (1) | ||||
| Simulated opalEnglish | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited); Note: Related high-risk name “Synthetic / Composite / Imitation Opal”. |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- 模造オパール／イミテーションオパール (not yet checked for this body — the entry's own Japanese name is shown)
- Name built by the GB/T naming rules (not listed as such)
- 仿欧泊 (GB/T 16552—2017 §5.2.1 a); basic name 欧泊)
- Mineralogical name
- Glass, resin or other product imitating opal without meeting synthetic-opal definition
- Trade names and synonyms
- Simulated opal (market name)
Four-language names
- 简体中文
- 仿欧泊
- 繁體中文
- 仿歐泊
- English
- Imitation Opal
- 日本語
- 模造オパール／イミテーションオパール
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Artificial products / Manufactured products
- Material domain
- Artificial products / Manufactured products
- Browsing family
- Imitation gem products
- Identity tier
- Artificial product type
- Mineral chemical class
- Mixed / composition-dependent
- Construction or treatment status
- Imitation; record actual material
What it is and how it's identified
The composition (phase) of Imitation Opal is registered as plastic, a conclusion taken from the CIBJO Blue Book 2024 definition of plastic, namely that plastic can be made to show play-of-colour to imitate opal. CIBJO only defines plastic and does not state that all Imitation Opal is made of plastic; glass and other imitation materials are not covered, and the actual material must be identified piece by piece.
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
Imitation Opal — composition (phase): plastic (made with play-of-colour to imitate opal)
CIBJO Gemmological Laboratories Book 2024
- Qualification
The clause we cite says, under “Plastic”, that plastic is also made with play-of-colour to imitate opal. It does not say every imitation opal is plastic; the glass and other imitations named in this entry's definition are outside that clause, so the material of a given piece has to be identified.
Source & check 2026-09-28
- Source
- Fact checked on
- 2026-09-28
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
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.
- eCFR (United States). 16 CFR Part 23 — Guides for the Jewelry, Precious Metals, and Pewter Industries.
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.
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| Page | Content | Status |
|---|---|---|
| Browsing family | Imitation gem products | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Imitation Opal 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.