On this page
UnderstandWhat it is, what people ask, how far this page goes
Unspecified-material term · Trade name: material identity unverified · Actual material to be verified
Quartz or glass showing a rainbow effect
Also known asIris quartz (conditional name) · Rainbow Crystal (not a recommended name) · Rainbow Quartz (conditional name)
An ambiguous market name: the rainbow effect may come from natural fractures, an artificial coating, glass or other causes, and must be explained piece by piece. Also known as Rainbow Quartz, Rainbow Crystal. 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 Quartz or glass showing a rainbow effect 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 Quartz or glass showing a rainbow effectIdentification points from the research literature
- Treatments and enhancements of Quartz or glass showing a rainbow effect2 registered treatments: status, stability, how common they are and identification leads
- Quartz or glass showing a rainbow effect 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 Quartz or glass showing a rainbow effectThe listing name to use; what must be disclosed before sale
- Standard clauses that define Quartz or glass showing a rainbow effectWhich 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
'Rainbow quartz' is an ambiguous, multi-sense market term whose underlying material and treatment are both undetermined: it may refer to material whose rainbow colour arises from fractures or coatings, or to synthetic glass or another product. The cited sources give no unified definition, and this entry makes no assertion about its material or treatment. By way of reference, iridescence in natural quartz has two physical mechanisms: thin-film interference (interference from a film nanometres to micrometres thick) and interference from repetitive substructures (diffraction gratings). In minerals, many fractures, filled or unfilled, display iridescence through thin-film effects; iridescent quartz (iris quartz) from geodes in India's Deccan basalts shows iridescence because periodic etch defects on crystal faces form a diffraction grating. These mechanisms show that a 'rainbow/iridescent appearance' can arise from several different causes, so appearance alone cannot establish material or origin.
Scope: Used only to explain that 'Caihong' (rainbow quartz) is an ambiguous market name whose material and treatment are undetermined; the physical mechanism of the iridescence effect in natural quartz is given for reference only, not as a basis for determining material or treatment.
Sources G&G Spring 2017
Where it forms
Material/product undetermined; no specific geological environment applies
Sources G&G Spring 2017
(Reference) natural iridescent quartz occurs in basalt geodes (e.g., India's Deccan Traps)
Sources G&G Spring 2017
How it forms, step by step
Establish that Quartz or glass showing a rainbow effect (Chinese trade name: caihong; material unverified) is an ambiguous market term with undetermined material and treatment.
(Reference) iridescence in natural quartz can arise from thin-film interference or from diffraction gratings (periodic substructures/etch defects).
(Reference) many fractures in minerals show iridescence via thin-film effects, so appearance cannot fix material or origin.
Link to appearance
A 'rainbow' look is an ambiguous description; in natural quartz it can arise from thin-film interference or diffraction gratings, and commercially it may come from fractures, coatings or synthetic products — appearance alone cannot prove identity.
Sources G&G Spring 2017
Timescale
The sources give no timescale for the material this name denotes (material undetermined).
Causes of colour and optical effects
(Reference) iridescence in natural quartz arises either from thin-film interference or from interference by repetitive substructures (diffraction gratings).
Evidence grade AScope: States the physics of iridescence in natural quartz; not tied to any specimen of the market name.
(Reference) many fractures in minerals, filled or unfilled, display iridescence through thin-film effects; iridescent quartz from Deccan basalt geodes shows iridescence because periodic etch defects on crystal faces form a diffraction grating.
Evidence grade AScope: States the cause of natural iridescent quartz and fracture iridescence; not used to judge a 'rainbow quartz' specimen.
How it is identified
The colour and inclusion appearance of 'rainbow-quartz-market' cannot establish whether a stone is natural, synthetic or treated: quartz varieties that look alike may differ entirely in composition, growth history and treatment, and synthetic and natural quartz share essentially the same composition and physical properties, so the unaided eye cannot separate them. Laboratory identification rests on measurable properties and the division of labour between instruments — a polariscope with a conoscope lens can judge colour-zoning orientation from extinction and optic-axis readings, a refractometer gives refractive-index values, and EDXRF with infrared spectroscopy supplies chemical and structural fingerprints. Limitations: some methods depend on how the stone was cut and on comparison with reference material, and the final conclusion must be issued by an accredited gemological laboratory through testing rather than inferred from appearance.
Evidence grade AScope: Identification and separation points; testing must be performed by an accredited gemological laboratory, and no self-test thresholds are given.
Sources G&G Summer 2014 · CIBJO Gemstone Book 2022
Other research findings
'Rainbow quartz' is an ambiguous market term that may refer to fractures, coatings, synthetic glass or other products; both material and treatment are undetermined, with no unified definition in the cited sources.
Evidence grade CScope: States the term's ambiguity and undetermined status; presumes no specific material or treatment.
Limits of this research
- Research status: Only partial material-specific findings found; gaps are stated as gaps
- Quartz or glass showing a rainbow effect (Chinese trade name: caihong; material unverified) is an ambiguous market term with no authoritative definition in the cited sources; material and treatment are undetermined.
- This record makes no material or treatment attribution; the iridescence mechanisms are reference only.
- The GB/T full texts are not obtainable; no clause text was verified and no classification table was invented.
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
- Quartz or glass showing a rainbow effect (state the actual material and how the effect was produced)
GB/T 16552—2017 5.1.1 c), 5.3.4
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
"Quartz or glass showing a rainbow effect (Chinese trade name: caihong; material unverified)" is a market name rather than a mineral species name; before using it, verify: Trade name rather than a mineralogical species name.
What this means for you
Before buying, check the recommended listing name "Quartz or glass showing a rainbow effect (state the actual material and how the effect was produced)" 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
- Trade name rather than a mineralogical species name.
- Suggested listing name
- Quartz or glass showing a rainbow effect (state the actual material and how the effect was produced)
Treatments and identification leads
Registered treatmentsThe registered treatments for Quartz or glass showing a rainbow effect are dyeing and heat treatment. Values not givenDyeing has the status treated and a prevalence of common, with stability and identification leads recorded as “—”; heat treatment has the status treated and a prevalence of occasional, with stability and identification leads recorded as “—”. A value recorded as “—” means the cited source gives no value, not “none”.
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| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| dyeingApplies only to: iris quartzStatus: treated | commonly | — | — | — | — |
| heatingApplies only to: iris quartzStatus: treated | occasionally | — | — | — | — |
Where each treatment acts (schematics): Dyed · Heated / Heat-treated
“—” means the cited source gives no value for that item, not “none”. Source: CIBJO Gemstone Book 2022
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
VerifyNames, standards, technical facts, clauses and sources
Names
Besides Quartz or glass showing a rainbow effect, the name register records "Iris quartz", "Rainbow Crystal" and "Rainbow Quartz", for which no restriction on use as a name is recorded (CIBJO Gemmological Laboratories Book 2024 §7.2.1.116 “Iris quartz”; CIBJO Gemstone Book 2022 Annex 8 “Iris Quartz”).
Recommended listing nameThe suggested listing name for Quartz or glass showing a rainbow effect is “rainbow quartz (with the actual material and cause stated)”. Trade and mineralogical namesIt is a trade name whose material identity is undetermined, and an ambiguous market name that may refer to fractures, coatings, synthetic glass or other products. Chinese standard nameUnder GB/T 16552—2017, the corresponding national-standard name is rock crystal (the name itself is not listed in the original). Names in four languagesThe four-language names cover Simplified Chinese, Traditional Chinese, English (Quartz or glass showing a rainbow effect) and Japanese (a market name with the material not identified). Institution usageThe wording of GIA, FTC, CIBJO and Gem-A for this name is not yet verified by this site; the entry's own English name is shown and does not represent their position, with the accompanying qualification that it is the Chinese trade name caihong and the material is unverified; the GSJ (Japan) wording is also not yet verified by this site, and the entry's own Japanese name is shown. Trade and mineralogical namesAmong the registered names, Iris quartz is a market name, matched only once its conditions are confirmed, based on the CIBJO Gemmological Laboratories Book 2024 and the CIBJO Gemstone Book 2022. Candidate search termsRainbow Quartz is used only as a candidate search term; Rainbow Crystal is not matched to this entry, must not be cross-referenced with it, and is only a noise term.
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 (3) | ||||
| Iris quartzEnglish | market name | matched only once the condition is confirmed | no restriction recorded | CIBJO Gemmological Laboratories Book 2024 §7.2.1.116 “Iris quartz”; CIBJO Gemstone Book 2022 Annex 8 “Iris Quartz” |
| Rainbow CrystalEnglish | market name | never matched to this entry | no restriction recorded | editorial ruling (no clause cited); Note: This is a loose descriptive phrase, not a name that identifies this material, so it is not matched to this entry. |
| Rainbow QuartzEnglish | market name | search candidate only | no restriction recorded | editorial ruling (no clause cited) |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- 「レインボークリスタル」材質未同定の市場名 (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)
- 水晶 (GB/T 16552—2017 §5.1.1 c))
- Mineralogical name
- Ambiguous market term that may refer to fractures, coatings, synthetic glass or another product
- Trade names and synonyms
- Rainbow Quartz (market name; conditional name) · Rainbow Crystal (market name; not a recommended name) · Iris quartz (market name; conditional name)
Four-language names
- 简体中文
- 彩虹水晶
- 繁體中文
- 彩虹水晶
- English
- Quartz or glass showing a rainbow effect (Chinese trade name: caihong; material unverified)
- 日本語
- 「レインボークリスタル」材質未同定の市場名
Qualifiers stripped from the headline name
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Material identity unspecified
- Material domain
- Unspecified-material term
- Browsing family
- Bead-form and unidentified trade terms
- Identity tier
- Trade name: material identity unverified
- Mineral chemical class
- Mixed / composition-dependent
- Construction or treatment status
- Actual material to be verified
What it is and how it's identified
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”.
Care
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.
Quartz or glass showing a rainbow effect — 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
- treated
- Applies only to
- iris quartz
Source & check 2026-09-28
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, Iris Quartz, p.69-70; §6.2 j (locator checked 2026-09-28)
- Fact checked on
- 2026-09-28
Quartz or glass showing a rainbow effect — care (chemicals): Treatments with dye, oil, resin, wax or plastic are not permanent; keep it away from all solvents (including dish-washing liquids), chemicals and heat.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code k
- Treatment state
- treated
- Only after these treatments
- dyeing
- Applies only to
- iris quartz
Source & check 2026-09-28
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, Iris Quartz, p.69-70; §6.2 k (locator checked 2026-09-28)
- Fact checked on
- 2026-09-28
How far testing can go
For Quartz or glass showing a rainbow effect in trade, the reported frequency of dyeing is “commonly”.
CIBJO Gemstone Book 2022
- Treatment state
- treated
- Treatment
- dyeing
- Applies only to
- iris quartz
- Qualification
The source row is for dyed iris quartz.
Source & check 2026-09-28
- Source
- Fact checked on
- 2026-09-28
For Quartz or glass showing a rainbow effect in trade, the reported frequency of heating is “occasionally”.
CIBJO Gemstone Book 2022
- Treatment state
- treated
- Treatment
- heating
- Applies only to
- iris quartz
- Qualification
The source row is for iris quartz that is heated and then quenched.
Source & check 2026-09-28
- Source
- Fact checked on
- 2026-09-28
Quartz or glass showing a rainbow effect — criteria for distinction from other varieties: Iris quartz is rock crystal containing iridescent fractures, reflecting rainbow colours.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Applies only to
- iris quartz
- Qualification
The source entry covers only iridescence from fractures in rock crystal; goods sold as Caihong Shuijing (rainbow crystal) may also be coated quartz or glass, which that entry does not cover.
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.
Clause-level definitions
The clause-level definition for Quartz or glass showing a rainbow effect rests on the CIBJO Gemmological Laboratories Book 2024, under the term Iris quartz, defined as rock crystal containing iridescent fractures that reflect rainbow colours. The cross-check result is that it is defined directly by CIBJO, and no identically named English entry was found in this edition of the GB/T annex.
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| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Iris quartz | 7.2.1.116 | Iris quartz is rock crystal containing iridescent fractures, reflecting rainbow colours | Defined directly by CIBJO; no identically named English entry was found in this edition of the GB/T annex. |
Evidence and sources
Authority basis and clause sources
Sources
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 | Bead-form and unidentified trade terms | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Quartz or glass showing a rainbow effect 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.