On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Mineral species · Natural identity; treatment status unknown
Danburite
A silicate mineral species listed in Annex A.1 of GB/T 16552-2017. Danburite is unrelated to citrine and topaz and must not be confused with them because of similar Chinese names. 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 Danburite 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 DanburiteHow far lab testing can go and whether a synthetic exists
- Caring for and wearing DanburiteCleaning, heat, chemicals and light, as the cited sources give them; durability indicators and wearing advice
- Hardness, density and refractive index of DanburiteEach value with its source and check date
- Danburite in English, Chinese and Japanese; national standard namesNames in four languages, the GB/T standard name and the suggested listing name; and: Which of GIA, FTC, CIBJO and Gem-A have a name for it on record, and do those agree?
- Name origin and history of DanburiteWhere the name comes from
- Listing and disclosing DanburiteThe listing name to use; what must be disclosed before sale
- Standard clauses that define DanburiteWhich 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
Danburite is an orthorhombic borosilicate whose ideal formula is CaB2Si2O8 (equivalently CaB2(SiO4)2). The data sheet places it in evaporites, and in granite and metamorphosed carbonate rocks where hydrothermal activity has been at work. A GIA study of a newly documented Vietnamese occurrence at Luc Yen shows gem-quality danburite in a placer ringed by marble mountains, its origin possibly linked to certain pegmatite veins, much as at Madagascar's Anjanabonoina pegmatite. That material stands out for its honey yellow colour and high transparency and is rich in lanthanides; rare earth elements (REE) are credited with its yellow hue and blue long-wave UV fluorescence, with darker growth zones holding more REE and fluorescing more strongly blue.
Scope: Applies to the composition and occurrence of danburite as a borosilicate mineral and to its rare-earth-induced colour/luminescence; does not include quantitative genetic models beyond its two types of occurrence, evaporites and pegmatites.
Sources Handbook of Mineralogy · G&G Winter 2016
Where it forms
Metamorphosed carbonate rocks and granite where hydrothermal activity occurred (for example the marble mountains around Luc Yen, Vietnam)
Sources Handbook of Mineralogy
Evaporite settings
Sources Handbook of Mineralogy
Placer deposits surrounded by marble (gem material), possibly related to pegmatite veins
Sources G&G Winter 2016
How it forms, step by step
Boron and silicon are enriched in calcium-bearing hydrothermal-metamorphic or pegmatitic settings.
Sources Handbook of Mineralogy · G&G Winter 2016
Within granite/metamorphosed carbonate rocks or pegmatite veins, calcium, boron, and silicon combine to crystallize orthorhombic danburite.
Sources Handbook of Mineralogy · G&G Winter 2016
During growth, rare earth elements (lanthanides) are incorporated into the structure, producing growth zoning.
After weathering and transport, primary crystals concentrate in placers as gem material, with REE-richer zones showing stronger blue fluorescence.
Link to appearance
Danburite is colorless to white, wine-yellow, yellowish brown, or green, with vitreous to greasy luster; the Vietnamese REE-bearing material is honey yellow and fluoresces blue under long-wave UV, its growth zones correlating with REE content, with REE-richer zones fluorescing more strongly blue.
Sources G&G Winter 2016 · Handbook of Mineralogy
Timescale
The source does not state an absolute geological timescale for danburite formation.
Sources Handbook of Mineralogy · G&G Winter 2016 · CIBJO Gemstone Book 2022
Supporting findings
Danburite is found in evaporites, and in granite and metamorphosed carbonate rocks where hydrothermal activity has been at work.
Evidence grade BScope: A general occurrence summary, not a deposit model.
Sources Handbook of Mineralogy
Gem-quality danburite at Luc Yen, Vietnam, occurs in placers surrounded by marble, its formation possibly related to some pegmatite veins.
Evidence grade AScope: For that locality; not all danburite occurrences.
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Africa
- Anjanabonoina, MadagascarVery large crystals
Sources Handbook of Mineralogy
Asia
- An Phu, Luc Yen, Yen Bai, VietnamGem-quality danburite in an eluvial deposit
- Mogok area, Myanmar
Sources Handbook of Mineralogy
- Braldu Valley, Shigar, Karakoram
Sources Mindat: Danburite
North America
- Charcas, San Luis Potosí, MexicoLarge crystals
Sources Handbook of Mineralogy
- Danbury, Fairfield County, Connecticut, United States
Sources Mindat: Danburite
South America
- Alto Chapare, Cochabamba, Bolivia
Sources Handbook of Mineralogy
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
Danburite's honey yellow color and blue long-wave UV fluorescence are attributed to rare earth elements (REE), with darker zones richer in REE and more strongly blue-fluorescing; it was first discovered at Danbury, Connecticut, USA.
Evidence grade AScope: An REE-driven cause of color and luminescence; intensity varies with REE content.
Where the name comes from
The English name danburite is named after the locality at Danbury, Connecticut, USA.
Evidence grade BScope: Etymology explains the origin of the name only; it does not establish the material's composition, locality, naturalness, or treatment.
Sources Handbook of Mineralogy
Other research findings
Danburite is a borosilicate, ideally CaB2Si2O8 (CaB2(SiO4)2), orthorhombic.
Evidence grade BScope: Ideal composition; minor Na, Al, Fe, and REE may substitute.
Sources Handbook of Mineralogy · G&G Winter 2016
In the CIBJO standard, Danburite is listed as a mineral species / gemstone name, marked no treatment (always).
Evidence grade AScope: Confirms nomenclature and identity level only.
Sources CIBJO Gemstone Book 2022
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The sources give no absolute ages for danburite formation; GIA notes that the formation environment of Vietnamese danburite remains an ongoing research project.
- The specific diagenetic process of the evaporite occurrence is not detailed in the cited sources.
- The exact site of REE incorporation (e.g. substitution at the Ca site) is an inference in the source and not fully confirmed.
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
- Danburite
GB/T 16552—2017 Table A.1 “Danburite” · IMA Mineral List 2026-07 “Danburite”
Construction or treatment status
Natural identity; treatment status unknown
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
Danburite is Danburite; use "Danburite" for listings, and disclose any known treatments.
Evidence
- GB/T · Table A.1, row 赛黄晶 (Danburite)
What this means for you
Before buying, check the recommended listing name "Danburite" 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
Care and wear
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.
Care
Danburite — 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
- any treatment state
Source & check 2026-09-25
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, Danburite, p.50; §6.2 j (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
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
The care (cleaning) conclusion for Danburite is that it must not be cleaned ultrasonically; this conclusion applies regardless of treatment status, whether or not the stone has been treated. The source is the CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022), which registers danburite in its Danburite row.
This table scrolls sideways on narrow screens.
| Question | Matching entries |
|---|---|
| Can it go in an ultrasonic or steam cleaner? | care (cleaning) |
Durability and wearing
Toughness
Brittle
Fracture
Uneven to subconchoidal
Sources Handbook of Mineralogy
VerifyNames, standards, technical facts, clauses and sources
Names
Standard and listing namesThe Chinese standard name for Danburite is danburite (GB/T 16552—2017 Table A.1), the mineralogical name is Danburite, and the suggested listing name is also Danburite. Names in four languagesNames are registered in four languages: Simplified Chinese, Traditional Chinese, English (Danburite) and Japanese; for the GSJ (Japan), 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 wording recorded by this site comes from CIBJO, Danburite, sourced from the CIBJO Gemmological Laboratories Book 2024; the FTC text on file has no wording for Danburite, as checked by this site; GIA and Gem-A are unchecked. Bodies without a recorded wording show the entry's own English name, which does not represent the position of those bodies.
- GSJ (Japan) formal name
- ダンブリ石／ダンビュライト (not yet checked for this body — the entry's own Japanese name is shown)
- Chinese formal name
- 赛黄晶 (GB/T 16552—2017 Table A.1)
- Mineralogical name
- Danburite
Four-language names
- 简体中文
- 赛黄晶
- 繁體中文
- 賽黃晶
- English
- Danburite
- 日本語
- ダンブリ石／ダンビュライト
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
- Mineral species
- Mineral chemical class
- Silicates
- Construction or treatment status
- Natural identity; treatment status unknown
What it is and how it's identified
Danburite has the chemical composition CaB2(SiO4)2 and the phase danburite. It is crystalline and orthorhombic, commonly forming short prismatic crystals, and also occurs as massive or granular aggregates. Its Mohs hardness is 7, with one very indistinct cleavage; this site notes that hardness alone is not enough to judge durability. Density is 2.97–3.03 g/cm³: the cited clause gives 3.00 with a tolerance of ±0.03, from which these limits are derived. Optically it is anisotropic and biaxial, positive or negative; refractive index is 1.627–1.639, derived from the cited clause's 1.630–1.636 with a tolerance of ±0.003; birefringence is 0.006; and it is transparent. Untreated Danburite shows weak pleochroism that varies with colour; under long-wave UV fluorescence ranges from none to strong, light blue to bluish green, and short-wave fluorescence is usually weaker than long-wave. Magnification shows gas-liquid inclusions, mineral inclusions and growth striations, and the lustre is vitreous to greasy. In the UV-visible spectrum some stones show a 580nm doublet, and the mid-infrared region shows the characteristic danburite infrared absorption bands.
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
Danburite — nomenclature status: IMA status G: grandfathered (described before the IMA existed, and generally regarded as a valid species).
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Danburite — composition (chemistry): CaB2 (SiO4) 2
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): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Danburite — composition (phase): danburite
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Structure
Danburite — 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): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Danburite — 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): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Danburite — structure (crystal habit): usually stubby prisms, also massive or granular aggregates.
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): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Durability
Danburite — Mohs hardness: 7
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): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Danburite — cleavage: extremely incomplete in one direction
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): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Physical properties
Danburite — density: 2.97–3.03 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 3.00, with a stated tolerance of ±0.03. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Optical
Danburite — optic character: biaxial and anisotropic, with a positive or a negative optic sign.
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): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Danburite — refractive index: 1.627–1.639
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 1.630–1.636, with a stated tolerance of ±0.003. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Danburite — birefringence: 0.006
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): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Danburite — transparency: transparent.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Danburite — pleochroism: weak; it depends on the body colour.
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): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Danburite — fluorescence (overall): long wave none to strong, light blue to blue-green; fluorescence under short wave is usually weaker than under long wave.
GB/T 16553—2017
UV fluorescencelight blueblue-greennone–strongDots 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): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Danburite — spectrum (UV-visible): visible in some 580 nm double absorption peak
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): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Danburite — spectrum (infrared): Danburite's own diagnostic absorption bands appear in the mid-IR
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): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Danburite — magnification: gas-liquid inclusions, mineral inclusions, growth striations
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): §5.1.44 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
body colour2 sources compared
Danburite — body colour: yellow, colorless, brown, etc., pink-red (rare)
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 Phenakite, Topaz, Apatite 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): §5.1.44 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Danburite — body colour: yellow to brown, pink, colourless.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Amblygonite, Diaspore, Enstatite and other entries also name yellow or a yellowish colour.
- General note
- colour alone is not identity
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
How the sources relate
- GB/T 16553—2017 and CIBJO Gemmological Laboratories Book 2024
The two entries agree: yellow to brown, pink and colourless; GB/T 16553—2017 adds that pink is rare.
Quality factors
Danburite — quality factor (lustre): vitreous to greasy
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): §5.1.44 (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): 1.633 / 3; Closest values: 1Bi Yu, Green Nephrite Variety 1.621 / 3, 2Datolite 1.646 / 2.95, 3Dushan Yu / Dushan Jade 1.63 / 2.9, 4Brazilianite 1.611 / 2.97, 5Lazulite 1.627 / 3.12
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
There is no synthetic Danburite on the market. The tests the CIBJO laboratory protocol requires for Danburite, and what each method covers, are given in the protocol table on the laboratory testing page.
The tests the CIBJO laboratory protocol requires for this material, and what each method means, are in the protocol table on the laboratory testing page: §6.1.21.
How far testing can go
Danburite — synthetic counterpart on the market: No synthetic counterpart of this material is commercially available
CIBJO Gemstone Book 2022
- Treatment state
- any treatment state
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Clause-level definitions
Danburite has a direct clause-level definition in the CIBJO Gemmological Laboratories Book 2024, under the term Danburite: yellow to brown, pink, colourless, transparent; the cross-check result is defined directly by CIBJO, also appearing in the GB/T annex. Danburite also has an entry in the IMA mineral list, likewise under the term Danburite, defined as Danburite CaB2Si2O8, G 1839, cross-checked against the RRUFF/IMA mineral list master table, using public-domain data.
This table scrolls sideways on narrow screens.
| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Danburite | 7.2.1.69 | yellow to brown, pink, colourless; transparent | Defined directly by CIBJO; also present in the GB/T annex. |
| Danburite | IMA Mineral List entry | Danburite CaB2Si2O8 G 1839 | Cross-checked against the RRUFF/IMA master mineral list (public domain data). |
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.
- GIA – Gemological Institute of America (United States). Gem Encyclopedia.
- Gem-A – The Gemmological Association of Great Britain (United Kingdom).
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 |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Danburite 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.