On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Trade name: colour / appearance variety · Natural identity; treatment status unknown
Imperial Topaz
Also known asPrecious topaz
A commercial variety name for Topaz in medium reddish-orange to orange-red tones, with no strict colour-grade boundaries; heating, irradiation and coating must all be disclosed. Also known as Precious topaz. 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 Imperial Topaz 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 Imperial TopazIdentification points from the research literature; how far lab testing can go
- Treatments and enhancements of Imperial TopazThe enhancements and treatments the GB/T and JJA/AGL tables list
- Caring for and wearing Imperial TopazCleaning, heat, chemicals and light, as the cited sources give them; durability indicators and wearing advice
- Hardness, density and refractive index of Imperial TopazEach value with its source and check date
- Imperial Topaz 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?
- Name origin and history of Imperial TopazWhere the name comes from
- Listing and disclosing Imperial TopazThe 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
Imperial topaz is a trade colour-variety name for topaz (Al2(F,OH)2SiO4) in medium reddish-orange to orange-red tones. Topaz occurs chiefly in veins and cavities in granite, granite pegmatite and rhyolite, and in greisen, formed from high-temperature, volatile-rich pneumatolytic-hydrothermal fluids; it is also a product of high-grade metamorphism of aluminous, silica-rich, fluorine-bearing sediments and occurs as a heavy detrital mineral. Topaz has an exceptionally wide colour range — blue, green, yellow, orange, red, pink, purple and colourless — and is pleochroic (showing different colours in different crystal directions); the most valued colours are orangy red to red, and imperial topaz belongs to this warm-tone group. In 1768 the royal court in Portugal celebrated the discovery of imperial topaz.
Scope: Applies to the naming boundary of imperial topaz as a trade variety of topaz in warm colours (reddish orange to orange-red), and an overview of the formation / occurrence of topaz; 'imperial' is a trade colour name, not an independent mineral species.
Sources Handbook of Mineralogy
Where it forms
Veins and cavities in granite, granite pegmatite and rhyolite, and in greisen (high-temperature, volatile-rich pneumatolytic-hydrothermal fluids).
Sources Handbook of Mineralogy
A product of high-grade metamorphism of aluminous, silica-rich, fluorine-bearing sediments; also a heavy detrital mineral.
Sources Handbook of Mineralogy
How it forms, step by step
High-temperature, volatile-rich pneumatolytic-hydrothermal fluids crystallize topaz in veins and cavities of granite, pegmatite and rhyolite.
Sources Handbook of Mineralogy
High-grade metamorphism of aluminous, silica-rich, fluorine-bearing sediments can also produce topaz.
Sources Handbook of Mineralogy
Topaz may be transported by weathering to become a heavy detrital mineral.
Sources Handbook of Mineralogy
Link to appearance
Topaz has an exceptionally wide colour range (blue, green, yellow, orange, red, pink, purple, colourless) and is pleochroic; the most valued colours are orangy red to red, the warm-tone group to which imperial topaz belongs.
Sources GIA Topaz
Timescale
The sources give no specific geological timescale for topaz formation (1768 refers only to the historical discovery year).
Sources GIA Topaz
Related base materials
- Topaz (Al2(F,OH)2SiO4): Imperial topaz is a trade colour variety of topaz ranging from reddish orange to orange-red
Supporting findings
Topaz occurs in veins and cavities in granite, granite pegmatite and rhyolite, and in greisen, formed from high-temperature, volatile-rich pneumatolytic-hydrothermal fluids.
Evidence grade BScope: General occurrence of the species; not locality-specific.
Sources Handbook of Mineralogy
Topaz is also a product of high-grade metamorphism of aluminous, silica-rich, fluorine-bearing sediments and can occur as a heavy detrital mineral.
Evidence grade BScope: Describes metamorphic and detrital settings; no genetic controversy.
Sources Handbook of Mineralogy
Recorded localities
Authoritative sources name a single or principal locality.
South America
- Ouro Preto imperial topaz district, Minas Gerais, BrazilGIA: so far, commercial deposits are found only in the Ouro Preto area; main mines include Capão and Vermelhão
Sources GIA Gem Encyclopedia · Gems & Gemology Winter 1996
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
The most valued topaz colours are orangy red to red, the warm-tone group to which imperial topaz belongs.
Evidence grade AScope: A value/colour description; the colouring agent is not given by the source.
Sources GIA Topaz
Topaz is pleochroic, showing different colours in different crystal directions.
Evidence grade AScope: An optical-property statement.
Sources GIA Topaz
Where the name comes from
The origin of the trade name "imperial topaz" is not given in the cited sources. The etymology below belongs to the parent mineral topaz: the name goes back to Greek topazion, 'to seek', apparently a nod to Zabargad Island (Zabirget or St. Johns) in Egypt's Red Sea — a locality whose whereabouts long stayed hidden and which was known for olivine (peridot and chrysolite), called topaz since antiquity. This etymology belongs to the parent mineral, not to the trade-variety name "imperial topaz" itself.
Evidence grade BScope: The etymology explains only the origin of the name; it does not establish the material's composition, locality, naturalness, or treatment.
Sources Handbook of Mineralogy
How it is identified
Imperial topaz colour can resemble yellow-orange-brown other gemstones and treated topaz, so colour alone cannot settle its species or treatment status. Determination relies on laboratory instruments such as UV-visible, infrared, or Raman spectroscopy and compositional analysis by electron microprobe or LA-ICP-MS; origin and treatment judgements depend on reference data with uncertainty, and conclusions must be issued by an accredited laboratory. This entry provides no self-test method or threshold.
Evidence grade AScope: Appearance is insufficient to settle species and treatment; determination requires testing by an accredited laboratory, and this entry gives no self-identification criteria.
Sources CIBJO Gemstone Book 2022 · G&G Spring 2019
Other research findings
Imperial topaz is a trade colour-variety name for warm-toned (reddish-orange to orange-red) topaz (Al2(F,OH)2SiO4) and is not an independent mineral species.
Evidence grade AScope: Naming and variety classification; "imperial" is a trade colour name.
Sources GIA Topaz · Handbook of Mineralogy
In 1768 the royal court in Portugal celebrated the discovery of Imperial topaz; "Precious topaz" is a November birthstone and imperial topaz is the gem of the 23rd anniversary.
Evidence grade AScope: Historical/cultural record, not genesis.
Sources GIA Topaz
The GIA sources cited for this entry carry no record specific to imperial topaz, the warm-toned variety of topaz. The topaz size records given in the 1988 article belong to a yellow topaz (22,892 ct, then the heaviest faceted gemstone) and to blue topaz (the largest faceted natural-colour blue topaz, 21,005 ct); neither is imperial topaz.
Evidence grade AScope: States that the sources give no imperial-topaz-specific record and distinguishes the records of the topaz varieties. Records change over time; limited to the source year (1988).
Sources G&G Spring 1988
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The specific colouring mechanism of topaz (which element/colour centre produces the orange-red tone) is not given in the sources consulted; this record makes no colour-cause assertion.
- The trade-colour definition of imperial topaz rests on GIA's colour/value descriptions; no strict colour-range standard for the name is supplied by the sources.
- No absolute geological timescale for topaz formation is given by the sources.
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
- Imperial Topaz (orange to red topaz)
16 CFR Part 23 §23.24
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Heated / Heat-treated (via parent material), Irradiated (via parent material), Diffusion-treated (via parent material), Coated (via parent material)
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
"Imperial Topaz" is a market name rather than a mineral species name; before using it, verify: Trade name rather than a mineralogical species name.
Evidence
What this means for you
Before buying, check the recommended listing name "Imperial Topaz (orange to red topaz)" 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
- Imperial Topaz (orange to red topaz)
Care and wear
The item-by-item care advice that the GIA Care and Cleaning Guide gives for the whole class, and so for Imperial Topaz, is set out in full under care on the Topaz entry.
Care
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Durability and wearing
Toughness
Brittle
Fracture
Subconchoidal to uneven
Sources Handbook of Mineralogy
Daily wear
Hardness 8 gives good scratch resistance, but the mineral is brittle with one perfect basal cleavage: a hard blow or a sharp temperature change can split or break it, so protective settings or designs less exposed to knocks (pendants, pins) are preferable.
Care
No cleaning steps are given in the source; because of the perfect cleavage and brittleness, clean by hand with warm water, mild soap and a soft cloth, avoid ultrasonic/steam cleaning and thermal shock. Irradiated material should avoid prolonged heat or sunlight.
General guidance: LumaLark's general guidance inferred from the material's properties (hardness, toughness, cleavage); not text from the cited source, and not a guarantee for any specific piece.
Scope: This field describes the material's general properties and is not a finished-product durability promise; it gives no warranty of any specific piece's durability or safety, and the durability of treated (filled, dyed, coated) or composite/assembled material must be assessed separately.
Treatments and identification leads
One row per treatment, with three standards side by side: how often it occurs and how stable it is (CIBJO), its category in GB/T 16552—2017 Table B.1 (this site's paraphrase) and how the JJA/AGL 2025 table lists it. Each CIBJO value links to its entry under “Testing and market”, where the wording and source are given in full.
This table scrolls sideways on narrow screens.
| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| Heating | — | — | Optimization | — | — |
| Irradiation | — | — | Treatment | — | — |
| Diffusion | — | — | Treatment | — | — |
| Coating | — | — | Treatment | — | — |
“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16552—2017 Table B.1 (row for Topaz); JJA/AGL 2025
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
Besides Imperial Topaz, the name register records "Precious topaz", for which no restriction on use as a name is recorded.
Chinese standard nameThe GB/T 16552—2017 naming counterpart for Imperial Topaz is topaz, and Imperial Topaz itself is not listed in the standard. Trade and mineralogical namesThe trade name or synonym is Precious topaz, an English market name; the mineralogical name describes a commercial variety of topaz with a medium reddish-orange to orangey-red tone. Recommended listing nameThe suggested listing name is orange-red topaz (Imperial Topaz). Names in four languagesNames are registered in four languages: Simplified Chinese, Traditional Chinese, English (Imperial Topaz) and Japanese; for the GSJ (Japan) formal name, the Japanese name shown is the entry's own, and the wording used by the GSJ for it is not yet verified by this site. Institution usageOn authority wording, the English wording shown under GIA, FTC, CIBJO and Gem-A is Imperial Topaz, but the FTC and CIBJO texts on file have no wording for this name (checked), and GIA 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) | ||||
| Precious topazEnglish | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- インペリアルトパーズ (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)
- 托帕石 (GB/T 16552—2017 §5.1.1 c))
- Mineralogical name
- Medium reddish-orange to orange-red topaz trade variety
- Trade names and synonyms
- Precious topaz (market name)
Four-language names
- 简体中文
- 帝王托帕石
- 繁體中文
- 帝王託帕石
- English
- Imperial Topaz
- 日本語
- インペリアルトパーズ
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
- Trade name: colour / appearance variety
- Mineral chemical class
- Silicates
- Construction or treatment status
- Natural identity; treatment status unknown
Treatments listed by standards
GB/T Table B.1Treatments for Imperial Topaz are classified by this site applying the “Topaz” row of GB/T 16552—2017, Annex B, Table B.1: heating is listed as an optimization, and irradiation, diffusion and coating as treatments; the full row, with the effect column, is on the Topaz entry, and what Table B.1 is and how the cited grades are defined are on this site's Gem treatments page. JJA/AGL designationsThe table of principal gem names in the JJA/AGL (Japan) definitions and nomenclature of gemstones and ornamental materials, November 2025 revision, lists [colour] Topaz, with the gem name under “[colour] Topaz”, species Topaz, and colours yellow, brownish yellow and pinkish orange; the original does not name Imperial Topaz, nor does it say which tier the listed colours belong to. A note states that the OH type is also called Imperial Topaz.
GB/T 16552-2017, Annex B, Table B.1
Under the “Topaz” row of Table B.1: Heating Optimization; Irradiation Treatment; Diffusion Treatment; Coating Treatment. The full row, with the effect column, is on the Topaz page.
What Table B.1 is, and how the “see 5.4.1” grades are defined: see the GB/T 16552: optimization vs treatment page.
JJA/AGL (Japan) table of principal gem names, 2025
This table scrolls sideways on narrow screens.
| Gem name | Species | Colour | Listed in the table | Notes |
|---|---|---|---|---|
| [colour] Topaz | Topaz | yellow, brownish yellow, pinkish orange | listed under “[colour] Topaz” in the table; this page is related (the source does not name it); the OH type is also called imperial topaz; the cell spans the first two colour rows and the source does not say which |
JJA/AGL definitions and nomenclature (2025 revision), table of principal gem names, p.14
How to read the JJA/AGL table: see the Gem treatments page.
What it is and how it's identified
Material facts for Imperial Topaz are registered for topaz (the whole mineral species), not measured on Imperial Topaz itself; chemical composition, long-wave and short-wave UV fluorescence, UV-visible spectrum, infrared spectrum and magnification are in the material facts on the Topaz entry. Registered for topaz (the whole mineral species): crystalline, orthorhombic, prismatic crystals, often with lengthwise striations on the prism faces; Mohs hardness 8, with one perfect cleavage; optic character anisotropic, biaxial, optically positive. Density 3.49–3.57 g/cm³, worked out from the cited clause's 3.53 with a stated tolerance of ±0.04; refractive index 1.609–1.637, worked out from the cited clause's 1.619–1.627 with a stated tolerance of ±0.010; birefringence 0.008–0.01. Also registered for topaz (the whole mineral species): chatoyancy visible but rare; pleochroism, untreated, weak to moderate; lustre, untreated, vitreous. The source is GB/T 16553—2017 Gems — Testing.
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, long-wave UV luminescence, short-wave UV luminescence, UV-visible spectrum, infrared spectrum, magnification: these whole-class features are given in the cited clause for topaz (the whole mineral species), so they are not repeated on the Imperial Topaz page; see the material facts on the Topaz entry.
Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of Imperial Topaz (how to read class-level values).
Structure
Imperial Topaz — structure (overall): crystalline
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- topaz (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.13 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Imperial Topaz — structure (crystal system): orthorhombic
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- topaz (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.13 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Imperial Topaz — structure (crystal habit): prismatic; faces usually striated lengthwise
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- topaz (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.13 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Durability
Imperial Topaz — Mohs hardness: 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
- What this covers
- topaz (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.13 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Imperial Topaz — cleavage: perfect in one direction
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- topaz (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.13 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Physical properties
Imperial Topaz — density: 3.49–3.57 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- topaz (the whole mineral species)
- Qualification
The clause we cite gives 3.53, with a stated tolerance of ±0.04. The range shown here is worked out from that.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.13 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Optical
Imperial Topaz — optic character: biaxial, optically positive (anisotropic)
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- topaz (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.13 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Imperial Topaz — refractive index: 1.609–1.637
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- topaz (the whole mineral species)
- Qualification
The clause we cite gives 1.619–1.627, with a stated tolerance of ±0.010. The range shown here is worked out from that.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.13 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Imperial Topaz — birefringence: 0.008–0.01
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- topaz (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.13 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Imperial Topaz — pleochroism: weak to moderate. Yellow: brownish yellow, yellow and orange-yellow; brown: yellowish brown and brown; red and pink: light red, orange-red and yellow; green: blue-green and light green; blue: different shades of blue.
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- topaz (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.13 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Imperial Topaz — optical effect (chatoyancy): seen; rare
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- topaz (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.13 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
- CIBJO definitions
- chatoyancy
Quality factors
Imperial Topaz — quality factor (lustre): vitreous
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- topaz (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.13 (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): 1.623 / 3.53; Closest values: 1Hemimorphite 1.625 / 3.45, 2Glass 1.585 / 3.4, 3Artificial Strontium Aluminate Borate 1.665 / 3.39, 4Synthetic Jadeite 1.66 / 3.34, 5Peridot 1.672 / 3.38
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 CIBJO laboratory protocol covers Imperial Topaz under “Topaz” (§6.1.85): see identification on the Topaz entry; the required tests are listed on the CIBJO laboratory protocol table for Topaz.
How far testing can go
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.
- GIA – Gemological Institute of America (United States). Gem Encyclopedia.
- Gem-A – The Gemmological Association of Great Britain (United Kingdom).
- eCFR (United States). 16 CFR § 23.24 — Disclosure of treatments to gemstones. In: 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.
This table scrolls sideways on narrow screens.
| Page | Content | Status |
|---|---|---|
| Browsing family | Other silicate minerals | Live |
| Treatments recorded for this material | Heated / Heat-treated (via parent material), Irradiated (via parent material), Diffusion-treated (via parent material), Coated (via parent material) | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Imperial Topaz 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.