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
Dioptase
A copper-bearing hydrous silicate mineral species, Cu6Si6O18·6H2O; its standard Chinese name corresponds to Dioptase, and a name sometimes used, literally "rhombic malachite", is not its standard name. 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 Dioptase forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify DioptaseHow far lab testing can go and whether a synthetic exists
- Caring for and wearing DioptaseCleaning, heat, chemicals and light, as the cited sources give them; durability indicators and wearing advice
- Hardness, density and refractive index of DioptaseEach value with its source and check date
- Dioptase 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 DioptaseWhere the name comes from
- Listing and disclosing DioptaseThe listing name to use; what must be disclosed before sale
- Standard clauses that define DioptaseWhich 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
Dioptase is a hydrous copper silicate and a secondary mineral of the oxidized zone of some copper deposits, commonly intergrown with chrysocolla and malachite. It crystallises and precipitates from copper- and silica-bearing supergene fluids within the oxidized zone, forming mainly prismatic to rhombohedral crystals, as well as indistinct crystalline aggregates and massive material. Dioptase shows a vivid emerald-green to blue-green color with a green streak and vitreous luster, transparent to translucent, and is one of the most attractive copper minerals and an important gem material.
Scope: Covers the origin and occurrence of dioptase as a secondary copper silicate mineral of the oxidation zone of some copper deposits; does not address synthetic materials.
Sources Handbook of Mineralogy
Where it forms
The oxidized/supergene zone of some copper deposits
Sources Handbook of Mineralogy
A secondary setting intergrown with chrysocolla, malachite, mimetite, wulfenite, cerussite, hemimorphite, fluorite and quartz
Sources Handbook of Mineralogy
How it forms, step by step
A copper ore body forms, made up of primary minerals such as copper sulfides.
Sources Handbook of Mineralogy
The ore body undergoes weathering and oxidation, producing copper-bearing supergene fluids enriched in silica.
Sources Handbook of Mineralogy
Within the oxidized zone, the hydrous copper silicate (dioptase) crystallises and precipitates from the fluids.
Sources Handbook of Mineralogy
Dioptase occurs intergrown with chrysocolla, malachite and others, forming prismatic to rhombohedral crystals or massive aggregates.
Sources Handbook of Mineralogy
Link to appearance
Dioptase shows a vivid emerald-green to blue-green color with a green streak and vitreous luster, transparent to translucent; crystals are typically prismatic to rhombohedral with perfect cleavage. Its color and appearance are the main reasons it is prized as a gem material.
Sources Handbook of Mineralogy
Timescale
These sources do not state an absolute geological timescale for dioptase formation.
Sources Handbook of Mineralogy
Supporting findings
Dioptase occurs as a secondary mineral within the oxidized zone of certain copper deposits.
Evidence grade BScope: Applies to the oxidized zone of some copper deposits, not all.
Sources Handbook of Mineralogy
Dioptase occurs in association with chrysocolla, malachite, mimetite, wulfenite, cerussite, hemimorphite, fluorite and quartz.
Evidence grade BScope: Describes dioptase's paragenesis, not a universal claim for all localities.
Sources Handbook of Mineralogy
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Africa
- Tsumeb, Namibia
Sources Handbook of Mineralogy
- Mindouli, Pool, Republic of the Congo
Sources Handbook of Mineralogy
- Kolwezi, Lualaba, Democratic Republic of the Congo
Sources Handbook of Mineralogy
Asia
- Altyn-Tyube, Karaganda Region, Kazakhstan
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.
Where the name comes from
Dioptase takes its name from two Greek words, "through" and "to see", because the crystal's cleavage directions become visible when it is viewed through.
Evidence grade BScope: This states only the origin of the name and does not establish the material's composition, locality, natural origin, or whether it was treated.
Sources Handbook of Mineralogy
Other research findings
Dioptase is a hydrous copper silicate with a composition of about 39% SiO2, 50% CuO and 11% H2O, corresponding to CuSiO3·H2O, with the structural formula Cu6[Si6O18]·6H2O.
Evidence grade BScope: Describes dioptase's chemical and structural composition.
Sources Handbook of Mineralogy
Dioptase takes its name from Greek words meaning ‘through’ and ‘to see’, a reference to the fact that a viewer can make out the crystal’s cleavage directions by looking through it.
Evidence grade BScope: Concerns naming and identity, not origin or treatment.
Sources Handbook of Mineralogy
Dioptase is emerald-green to blue-green with a green streak, vitreous luster, transparent to translucent, and is pyroelectric.
Evidence grade BScope: Describes appearance and physical properties without explaining the specific cause of color.
Sources Handbook of Mineralogy
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The only available source (Handbook of Mineralogy) does not quantify the P-T conditions or absolute age of dioptase formation.
- The source lists the emerald-green to blue-green color but does not explain the specific cause of color, so no claim is made here about what causes the color.
- The specific sources and concentrations of copper and silica in the supergene fluids are not described in this source.
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
- Dioptase
GB/T 16552—2017 Table A.1 “Dioptase”, 5.1.1 a) · CIBJO Gemmological Laboratories Book 2024 §7.2.1.75 “Dioptase”
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
Dioptase is Dioptase (Cu6Si6O18·6H2O); use "Dioptase" for listings, and disclose any known treatments.
What this means for you
Before buying, check the recommended listing name "Dioptase" 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
Care
Dioptase — care (chemicals): the Oxford Mineral Susceptibility Database lists dioptase (after Schumann 1992) as dissolving in nitric acid and in ammonia.
Mineral Sensitivity Database, Oxford (2021)
- Treatment state
- any treatment state
Source & check 2026-10-06
- Source
- K. Royce, “The Mineral Susceptibility Database” (MSD-2021.06), University of Oxford (2021), doi:10.5287/bodleian:r17kVJb7d: p.52, 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.
This table scrolls sideways on narrow screens.
| Question | Matching entries |
|---|---|
| Contact with acids, alkalis and household chemicals | the Oxford Mineral Susceptibility Database lists dioptase (after Schumann 1992) as dissolving in nitric acid and in ammonia |
Durability and wearing
Toughness
Brittle
VerifyNames, standards, technical facts, clauses and sources
Names
Besides Dioptase, the name register records "Dioptase", for which no restriction on use as a name is recorded; one further name in a non-Latin script is listed in the name register below (1 with no restriction recorded on use as a name).
Chinese standard nameThe Chinese formal name for Dioptase is not itself listed in GB/T 16552—2017; its naming counterpart in Table A.1 is the standard's own Chinese name for the mineral; the Japanese GSJ formal name is written in kanji. Trade and mineralogical namesBoth the mineralogical name and the trade name or synonym are Dioptase, with the chemical formula Cu6Si6O18·6H2O. Names in four languagesThe four-language names are given in Simplified Chinese, Traditional Chinese, English (Dioptase) and Japanese (a transliteration and a kanji name). Recommended listing nameThe suggested listing name is Dioptase. Institution usageAmong authority wordings, the CIBJO Gemmological Laboratories Book 2024 lists Dioptase, the FTC source text has no wording for this name (checked), and GIA and Gem-A have not been checked; 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 (2) | ||||
| DioptaseEnglish | synonym | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
| 透视石Simplified Chinese | synonym | matched automatically | no restriction recorded | GB/T 16552—2017 Table A.1 “Dioptase” |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- 翠銅鉱
- GB/T naming counterpart (this name is not in the standard)
- 透视石 (GB/T 16552—2017 Table A.1)
- Mineralogical name
- Dioptase (Cu6Si6O18·6H2O)
Four-language names
- 简体中文
- 翠铜矿
- 繁體中文
- 翠銅礦
- English
- Dioptase
- 日本語
- ダイオプテーズ／翠銅鉱
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
Material facts for Dioptase are registered for this variety itself: chemical composition Cu6Si6O18·6H2O, crystalline, trigonal, with a short prismatic habit; Mohs hardness 5, with three perfect cleavages; density 3.25–3.35 g/cm³ (the cited clause gives 3.30 with a stated tolerance of ±0.05, and the range is worked out from that). Dioptase is anisotropic, uniaxial, optically positive, with a refractive index of 1.643–1.72 (the cited clause gives 1.655–1.708 with a stated tolerance of ±0.012, and the range is worked out from that), birefringence 0.051–0.053, and transparency transparent to translucent. For the body colour of untreated Dioptase, GB/T 16553—2017 gives bluish green, green and similar colours (site qualification: colour items in other variety clauses in Chapter 5 of GB/T 16553—2017 also mention green or greenish tones), and the CIBJO Gemmological Laboratories Book gives deep to intense bluish green (site qualification: colour descriptions of other entries in CIBJO Chapter 7 also mention green or greenish tones). Site note: hardness alone is not enough to judge durability.
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
Dioptase — 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
Dioptase — composition (chemistry): Cu6Si6O18·6H2O
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Dioptase — composition (phase): dioptase
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Structure
Dioptase — structure (overall): crystalline
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Dioptase — structure (crystal system): trigonal
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Dioptase — structure (crystal habit): short prismatic
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Durability
Dioptase — Mohs hardness: 5
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 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Dioptase — cleavage: perfect in three directions
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Physical properties
Dioptase — density: 3.25–3.35 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 3.30, with a stated tolerance of ±0.05. The range shown here is worked out from that.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Optical
Dioptase — optic character: anisotropic, uniaxial, optically positive
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Dioptase — refractive index: 1.643–1.72
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 1.655–1.708, with a stated tolerance of ±0.012. The range shown here is worked out from that.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Dioptase — birefringence: 0.051–0.053
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Dioptase — transparency: transparent to translucent.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Dioptase — pleochroism: weak, varying with colour
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Dioptase — fluorescence (overall): none
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Dioptase — spectrum (UV-visible): 550 nm broad absorption band
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Dioptase — spectrum (infrared): mid-IR bands characteristic of dioptase
GB/T 16553—2017
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Dioptase — magnification: gas-liquid inclusions, mineral inclusions, growth striations, obvious doubling (birefringence).
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
body colour2 sources compared
Dioptase — body colour: blue-green, green and similar colours
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 Aquamarine, Malachite, Emerald and other variety clauses also name green or a greenish colour.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Dioptase — body colour: Dark to intense bluish green.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Aquamarine, Chrysocolla, Lagoon Tourmaline and other entries also name green or a greenish 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
Both list bluish green; the CIBJO Gemmological Laboratories Book specifies a deep, intense tone, and GB/T 16553—2017 also lists green.
Quality factors
Dioptase — quality factor (lustre): vitreous
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.41 (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): 1.681 / 3.3; Closest values: 1Fei Cui / Jadeite Jade 1.683 / 3.35, 2Tanzanite 1.696 / 3.28, 3Peridot 1.672 / 3.38, 4Hydrogrossular 1.7 / 3.35, 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
Testing and market
Which tests the CIBJO laboratory protocol requires for Dioptase, and what each method means, are set out in the protocol table on the laboratory testing page. No synthetic counterpart of Dioptase is on the market.
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: §6.1.26.
How far testing can go
Dioptase — 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
Dioptase is listed under the entry name Dioptase in the gem materials list and definitions chapter of the CIBJO Gemmological Laboratories Book 2024, defined as dark to intense bluish green, transparent to translucent; the cross-check result is that it is defined directly by CIBJO and also appears in the GB/T annex. Dioptase also has an entry in the IMA Mineral List under the name Dioptase, given as Dioptase CuSiO3(H2O), cross-checked against the RRUFF/IMA master mineral list, which is public domain data.
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| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Dioptase | 7.2.1.75 | Dark to intense bluish green, transparent to translucent | Defined directly by CIBJO; also present in the GB/T annex. |
| Dioptase | IMA Mineral List entry | Dioptase CuSiO3(H2O) G 1798 | 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.
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 | Other silicate minerals | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Dioptase 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.