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UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Mineral species · Natural identity; treatment status unknown
Dolomite
A calcium magnesium carbonate mineral species with the formula CaMg(CO3)2; together with calcite it is a constituent mineral of marble. 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 Dolomite forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify DolomiteHow far lab testing can go and whether a synthetic exists
- Caring for and wearing DolomiteDurability indicators and wearing advice
- Hardness, density and refractive index of DolomiteEach value with its source and check date
- Dolomite 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 DolomiteWhere the name comes from
- Listing and disclosing DolomiteThe listing name to use
- Standard clauses that define DolomiteWhich 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
Dolomite is the carbonate mineral CaMg(CO3)2, pairing calcium with magnesium. It may form by diagenesis or by hydrothermal metasomatism of limestone, and it is a primary phase in hypersaline sedimentary settings; it forms a major constituent of certain marbles and contact-metamorphic rocks, appears as gangue in hydrothermal veins, and occurs in carbonatites and ultramafic rocks. Dolomite heads its own mineral group and forms two solid-solution series, one with ankerite and one with kutnohorite, and it is noted for crystal aggregates of saddle shape.
Scope: Covers the origin, occurrence and composition of dolomite as a natural calcium magnesium carbonate mineral; does not address synthetic material or trade variety names.
Sources Handbook of Mineralogy · CIBJO Gemstone Book 2022
Where it forms
Limestone that diagenesis or hydrothermal metasomatism has altered; hypersaline sedimentary settings.
Sources Handbook of Mineralogy
Contact-metamorphic rocks together with marbles; as gangue within hydrothermal veins; also in carbonatites and ultramafic rocks
Sources Handbook of Mineralogy
How it forms, step by step
In hypersaline sedimentary environments, dolomite may precipitate directly as a primary phase.
Sources Handbook of Mineralogy
Within limestone, dolomite forms by diagenesis or hydrothermal metasomatism, in which magnesium-bearing fluids replace the pre-existing carbonate components.
Sources Handbook of Mineralogy
Under contact and regional metamorphism, dolomite becomes a component of marbles and some metamorphic rocks; it also crystallizes in hydrothermal veins, carbonatites, and ultramafic rocks.
Sources Handbook of Mineralogy
Link to appearance
Dolomite ranges from colorless and white to yellow, brown, or pale pink, with vitreous to pearly luster; its crystals are typically rhombohedral and, through curved crystal faces, form the characteristic saddle-shaped aggregates.
Sources Handbook of Mineralogy · CIBJO Gemstone Book 2022
Timescale
The source does not state a timescale or absolute age for dolomite formation.
Sources Handbook of Mineralogy
Supporting findings
Dolomite may develop through diagenesis or through hydrothermal metasomatism that alters limestone, and it is a primary phase where sedimentary environments are hypersaline; it forms a major constituent of certain marbles and contact-metamorphic rocks, appears as gangue within hydrothermal veins, and is found in carbonatites and ultramafic rocks.
Evidence grade BScope: Applies to natural dolomite occurrences and environments; excludes synthetic dolomite.
Sources Handbook of Mineralogy
Dolomite forms through replacement during diagenesis, in which magnesium-bearing fluids react with limestone to replace its carbonate components with CaMg(CO3)2.
Evidence grade BScope: Applies to dolomite formation by replacement of limestone; fluid chemistry and P-T are not quantified.
Sources Handbook of Mineralogy
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Africa
- Bou Azer District, Ouarzazate, MoroccoPictured specimen is cobaltoan dolomite
Sources Mindat: Dolomite
Europe
- Eugui, Navarre, Spain
Sources Handbook of Mineralogy · Mindat: Dolomite
North America
- Franklin, Sussex County, New Jersey, United States
Sources Mindat: Dolomite
Seas and coasts
- Worldwide
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
Dolomite commemorates Dieudonne (Déodat) Sylvain Guy Tancrède de Gratet de Dolomieu (1750–1801), a French naturalist and geologist whose work aided early descriptions of the species in dolostone.
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
Dolomite has the formula CaMg(CO3)2 and belongs to the dolomite group, forming two solid-solution series—one with ankerite and one with kutnohorite.
Evidence grade BScope: Describes formula, group, and the two solid-solution series; does not address end-member proportion measurements.
Sources Handbook of Mineralogy
Déodat de Dolomieu (1750–1801), the French geologist and naturalist, is commemorated in the mineral’s name; his early writings on the species found in dolostone were among its first descriptions.
Evidence grade BScope: Concerns the scientific history of the species' naming; not a genetic or identification criterion.
Sources Handbook of Mineralogy
Under the CIBJO definition, only materials formed completely by nature without human intervention qualify as 'natural'; dolomite, as a natural mineral species, satisfies this identity boundary.
Evidence grade AScope: Defines its status as a natural material; does not assess locality or quality grade.
Sources CIBJO Gemstone Book 2022
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The source does not state a timescale or absolute age for dolomite formation.
- The specific fluid chemistry, temperature, and pressure conditions of dolomitization are not quantified in this source.
- End-member proportions of the two solid-solution series (ankerite, kutnohorite) are not provided 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
- Dolomite
GB/T 16552—2017 Table A.2 “Dolomite” · CIBJO Gemmological Laboratories Book 2024 §7.2.1.76 “Dolomite”
Construction or treatment status
Natural identity; treatment status unknown
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
Dolomite is Dolomite (CaMg(CO3)2); use "Dolomite" for listings, and disclose any known treatments.
What this means for you
Before buying, check the recommended listing name "Dolomite" and any disclosed treatments on this page, and ask the seller for a grading report if in doubt.
- Last reviewed
- 2026-09-01
Care and wear
No institutional care guidance is registered for this material yet; below are its durability indicators and general guidance.
Durability and wearing
Numbers in curly braces, such as {111}, are crystallographic face symbols (Miller indices): each marks a set of crystal faces or cleavage planes. They are reproduced as written in the cited source.
Daily wear
Dolomite ranks only 3.5–4 on the Mohs scale and is brittle, with perfect cleavage on {1011} and a subconchoidal fracture; it scratches easily and splits along cleavage, so it is best kept as a display piece or protected jewellery rather than worn daily.
Care
As a soft, brittle material, clean it with warm soapy water and a soft brush; avoid ultrasonic and steam cleaners and heat, and avoid acidic, chlorine-based or abrasive cleaners. Store it apart from harder gems.
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 does not constitute a durability or safety guarantee for any specific finished product; the durability of treated (filled, dyed, coated) or composite pieces must be assessed separately.
VerifyNames, standards, technical facts, clauses and sources
Names
Standard and listing namesThe Chinese formal name for Dolomite comes from GB/T 16552—2017 Table A.2 (marble); the suggested listing name is Dolomite. Trade and mineralogical namesThe mineralogical name is Dolomite, with the chemical formula CaMg(CO3)2. Institution usageOn authority wording, CIBJO records Dolomite, in the CIBJO Gemmological Laboratories Book 2024; the FTC text on file has no wording for this name (checked); GIA and Gem-A are unchecked, and bodies without a recorded wording show the entry's own English name, which does not represent the position of those bodies. Japanese namesJapan's GSJ formal name is given as a kanji name with a katakana reading. Names in four languagesNames are given in four languages: Simplified Chinese, Traditional Chinese, English (Dolomite) and Japanese (katakana and kanji forms). Dolomite's identity tier is mineral species, and its browsing family is carbonate minerals.
- GSJ (Japan) formal name
- 苦灰石（ドロマイト）
- Chinese formal name
- 白云石 (GB/T 16552—2017 Table A.2, row “Marble”)
- Mineralogical name
- Dolomite (CaMg(CO3)2)
Four-language names
- 简体中文
- 白云石
- 繁體中文
- 白雲石
- English
- Dolomite
- 日本語
- ドロマイト／苦灰石
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural inorganic gem materials
- Browsing family
- Carbonate minerals
- Identity tier
- Mineral species
- Mineral chemical class
- Carbonates
- Construction or treatment status
- Natural identity; treatment status unknown
What it is and how it's identified
The chemical composition of Dolomite is CaMg(CO3)2, which may contain Fe, Mn, Pb, Zn and other elements; structure crystalline or crystalline aggregate, trigonal, with a rhombohedral habit, commonly in granular or massive aggregates. Mohs hardness is registered as 3.5–4 from the Handbook of Mineralogy and as 3–4 from GB/T 16553—2017. Cleavage three directions, perfect, generally not visible in aggregates; untreated, cleavage is perfect and tenacity brittle, and it effervesces with a drop of hydrochloric acid. Density 2.86–3.2 g/cm³; optical character uniaxial, negative, commonly an anisotropic aggregate; refractive index 1.505–1.743, birefringence 0.179–0.184, where the site note explains that the clause has finer sub-ranges and the overall value is used. Untreated, lustre is vitreous to pearly.
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
Dolomite — 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
Dolomite — composition (chemistry): CaMg (CO3) 2, elements such as Fe,Mn,Pb and Zn may be contained.
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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Dolomite — composition (phase): dolomite
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Structure
Dolomite — structure (overall): crystalline, or else a crystalline aggregate
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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Dolomite — structure (crystal system): trigonal
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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Dolomite — structure (crystal habit): rhombohedra; mostly granular or massive 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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Durability
Mohs hardness2 sources compared
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))
Dolomite — Mohs hardness: 3.5–4
Handbook of Mineralogy
Source & check 2026-09-20
- Source
- Handbook of Mineralogy — Dolomite (Mineral Data Publishing): p. 1, Physical Properties (locator checked 2026-09-20)
- Fact checked on
- 2026-09-20
Dolomite — Mohs hardness: 3–4
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): §5.2.21 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Dolomite — cleavage: three directions of perfect cleavage, which aggregates usually do not show.
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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Dolomite — toughness: cleavage perfect; tenacity brittle
Handbook of Mineralogy
- Treatment state
- untreated
Source & check 2026-09-20
- Source
- Handbook of Mineralogy — Dolomite (Mineral Data Publishing): p. 1, Physical Properties (locator checked 2026-09-20)
- Fact checked on
- 2026-09-20
Dolomite — stability: effervesces on contact with hydrochloric acid
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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Physical properties
Dolomite — density: 2.86–3.2 g/cm³
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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Optical
Dolomite — optic character: uniaxial, optically negative; usually behaves as an anisotropic aggregate.
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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Dolomite — refractive index: 1.505–1.743
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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Dolomite — birefringence: 0.179–0.184
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- General note
- the clause has finer ranges
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Dolomite — transparency: transparent, translucent, opaque.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Dolomite — pleochroism: none to weak; cannot be measured on aggregates.
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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Dolomite — fluorescence (overall): varies with colour or origin
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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Dolomite — spectrum (UV-visible): non-characteristic
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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Dolomite — spectrum (infrared): Vibration of the carbonate ion produces diagnostic bands 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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Dolomite — magnification: cleavage, generally granular structure aggregate
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): §5.2.21 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
body colour2 sources compared
Dolomite — body colour: Colourless (white), light yellow to brown.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Magnesite, Datolite, Diaspore and other entries also name colourless.
- General note
- colour alone is not identity
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Dolomite — body colour: colorless or white, tinged yellow or brown.
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 Calcite, Smithsonite, Cassiterite and other variety clauses also name colourless.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.21 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
How the sources relate
- CIBJO Gemmological Laboratories Book 2024 and GB/T 16553—2017
The two entries agree: colourless or white, with yellow to brown tones.
Quality factors
Dolomite — quality factor (lustre): vitreous to pearly
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): §5.2.21 (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): 1.624 / 3.03; Closest values: 1Amblygonite 1.607 / 3.02, 2Brazilianite 1.611 / 2.97, 3Lazulite 1.627 / 3.12, 4Datolite 1.646 / 2.95, 5Dushan Yu / Dushan Jade 1.63 / 2.9
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 tests the CIBJO laboratory protocol requires for this material, and what each method means, are in the protocol table on the laboratory testing page: §6.1.27.
How far testing can go
Dolomite — 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
Dolomite — what the CIBJO laboratory protocol says to watch for: dye
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- any treatment state
Source & check 2026-09-26
- Source
- 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.
Clause-level definitions
Dolomite is defined directly in CIBJO Gemmological Laboratories Book 2024 under the term Dolomite, as colourless (white), light yellow to brown, transparent, translucent or opaque; the cross-check shows it is defined directly by CIBJO and also appears in the GB/T annex. Dolomite is also registered in the IMA Mineral List entry as Dolomite CaMg(CO3)2 G 1792, cross-checked against the RRUFF/IMA master mineral list using public domain data.
This table scrolls sideways on narrow screens.
| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Dolomite | 7.2.1.76 | Colourless (white), light yellow to brown, transparent, translucent, opaque | Defined directly by CIBJO; also present in the GB/T annex. |
| Dolomite | IMA Mineral List entry | Dolomite CaMg(CO3)2 G 1792 | Cross-checked against the RRUFF/IMA master mineral list (public domain data). |
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.
This table scrolls sideways on narrow screens.
| Page | Content | Status |
|---|---|---|
| Browsing family | Carbonate minerals | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Dolomite 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.