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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
Diaspore
Also known asColor-change diaspore · Csarite · Zultanite
An IMA-approved mineral species whose gem variety is sold under the registered trademark names Zultanite and Csarite; its colour-change effect and any treatment must be identified. 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 Diaspore forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify DiasporeHow far lab testing can go and whether a synthetic exists
- Caring for and wearing DiasporeCleaning, heat, chemicals and light, as the cited sources give them; durability indicators and wearing advice
- Hardness of DiasporeEach value with its source and check date
- Diaspore 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 DiasporeWhere the name comes from
- Listing and disclosing DiasporeThe listing name to use; what must be disclosed before sale
- Standard clauses that define DiasporeWhich 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
Diaspore has the formula AlO(OH) and is orthorhombic, dimorphous with böhmite. Most commonly it is the end product of diagenesis in bauxite deposits that arise through tropical weathering of alumino-silicate rocks; additionally it develops via hydrothermal alteration of aluminous minerals and can appear as a hydrothermal phase in certain alkalic pegmatites. Diaspore is an IMA-recognised independent mineral species; its gem variety carries market names such as Zultanite® or Csarite®, but a trade name is not an independent mineral species.
Scope: Applies to describing the origin, composition and occurrence of diaspore as an independent mineral species, and explains the relationship between its gem trade names (Zultanite®/Csarite®) and the mineral species; does not cover synthetic or imitation materials.
Sources Handbook of Mineralogy
Where it forms
A diagenetic product within bauxite deposits formed by tropical weathering
Sources Handbook of Mineralogy
Hydrothermal alteration setting of aluminous minerals
Sources Handbook of Mineralogy
Occurs as a hydrothermal phase in certain alkalic pegmatites
Sources Handbook of Mineralogy
How it forms, step by step
Alumino-silicate rocks undergo intense tropical weathering, and residual alumina enriches to form bauxite.
Sources Handbook of Mineralogy
During bauxite diagenesis, diaspore precipitates as a final product (AlO(OH)).
Sources Handbook of Mineralogy
Diaspore may also form by hydrothermal alteration of aluminous minerals and occurs as a hydrothermal mineral in some alkalic pegmatites.
Sources Handbook of Mineralogy
Diaspore is commonly associated with corundum, magnetite, margarite, chloritoid, spinel, chlorite, gibbsite, böhmite, sillimanite, lepidocrocite, hematite, kaolinite and halloysite.
Sources Handbook of Mineralogy
Link to appearance
Diaspore may be white, pale grey, colourless, greenish grey, brown, pale yellow, pink or lilac; within one specimen the hue can shift with the viewing direction, and the colour may run from brownish green under daylight to raspberry pink beneath artificial light. Its adamantine to vitreous luster (pearly on cleavage) together with platy and acicular crystals shapes its appearance; gem-quality diaspore from some localities is prized for its colour-change effect.
Sources Handbook of Mineralogy
Timescale
The source states no absolute geological timescale for diaspore formation.
Sources Handbook of Mineralogy
Supporting findings
Diaspore most often arises as the end product of diagenesis within bauxite deposits that originate when alumino-silicate rocks undergo tropical weathering; a second route is hydrothermal alteration of aluminous minerals, and it also appears as a hydrothermal phase in certain alkalic pegmatites.
Evidence grade BScope: Describes diaspore's general modes of formation; it does not infer the origin of any specimen.
Sources Handbook of Mineralogy
Diaspore is commonly associated with corundum, magnetite, margarite, chloritoid, spinel, chlorite, gibbsite and böhmite, among others.
Evidence grade BScope: Describes common diaspore associations; not every locality contains all of these minerals.
Sources Handbook of Mineralogy
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Asia
- Goshta District, Nangarhar, AfghanistanReportedly; purplish pink diaspore first seen on the market in 2020
Sources Gems & Gemology Summer 2020
Europe
- İlbir Mountain, near Pınarcık, Milas, Muğla, TürkiyeBefore the 2020 Afghan find, jewelry-size transparent diaspore was recovered only here
Sources Gems & Gemology Summer 2020
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
Diaspore's name comes from a Greek term meaning 'to scatter', alluding to how the mineral decrepitates in the blowpipe flame.
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
Other research findings
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.
Diaspore, formula AlO(OH), is orthorhombic; its habit is commonly tabular — flat parallel to {010} — and drawn out into acicular shapes along [001]. It is dimorphous with böhmite.
Evidence grade BScope: Describes diaspore's composition, habit and dimorphous relation; not a compositional analysis of any specimen.
Sources Handbook of Mineralogy
Within one diaspore sample the hue can shift with the direction of viewing, and the stone may change from brownish green under daylight to raspberry pink beneath artificial light.
Evidence grade BScope: Describes diaspore's colour-change phenomenon; the source gives no colour mechanism, so no mechanism is attributed.
Sources Handbook of Mineralogy
Diaspore is an IMA-recognised independent mineral species; Zultanite® and Csarite® are trade names for its gem variety, and a trade name is not an independent mineral species.
Evidence grade BScope: Defines the trade-name-to-diaspore-species relationship; it does not treat a trade name as an independent species.
Sources Handbook of Mineralogy
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The source states no absolute geological timescale for diaspore formation.
- The source does not attribute the colour of diaspore, including its colour-change effect, to any particular mechanism (such as Cr3+ or charge transfer), so none is assigned here; the mechanism can only be established by testing.
- The source gives no P-T conditions for gem-quality diaspore deposits.
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
- Diaspore
16 CFR Part 23 §23.24
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
Diaspore is Diaspore (IMA mineral species); gem variety known as Zultanite® or Csarite®; use "Diaspore" for listings, and disclose any known treatments.
Evidence
What this means for you
Before buying, check the recommended listing name "Diaspore" 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
Diaspore — 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, Diaspore, p.50; §6.2 j (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
Diaspore — care (wear): cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code b
- 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, Diaspore, p.50; §6.2 b (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
Care of Diaspore: according to the Diaspore row of the 2022 edition of the Gemstone Book (Blue Book) of the Coloured Stone Commission of CIBJO, The World Jewellery Confederation, diaspore must not be cleaned ultrasonically, regardless of treatment status; diaspore cleaves or fractures easily, so wear it with care, likewise regardless of treatment status.
This table scrolls sideways on narrow screens.
| Question | Matching entries |
|---|---|
| Can it go in an ultrasonic or steam cleaner? | care (cleaning) |
| Wearing limits (knocks, settings) | cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care |
Durability and wearing
Cleavage
{010} perfect; {110} distinct; {100} in traces only
How lab reports word it
A general LMHC wording rule also covers Diaspore (Information Sheet #9): see the LMHC rule “Colour-change stones”.
VerifyNames, standards, technical facts, clauses and sources
Names
Besides Diaspore, the name register records "Color-change diaspore", "Csarite" and "Zultanite", for which no restriction on use as a name is recorded.
Standard and listing namesDiaspore is not listed as a standard name in GB/T 16552—2017 Annex A but can be named directly, and the suggested listing name is Diaspore. Trade and mineralogical namesDiaspore is an IMA-approved mineral species; the gem variety is traded under the registered trademark trade names Zultanite and Csarite, and trade names and synonyms also include Color-change diaspore. Names in four languagesNames are registered in four languages: Simplified Chinese, Traditional Chinese, English (Diaspore) and Japanese. Institution usageOn authority wording, CIBJO records the wording Diaspore (CIBJO Gemmological Laboratories Book 2024); the FTC text on file has no wording for Diaspore (checked); GIA and Gem-A are unchecked; bodies without a recorded wording show the entry's own English name, which does not represent their position. Japanese namesThe Japanese name shown is the entry's own; the wording used by the GSJ (Japan) for it is not yet verified by this site.
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 (3) | ||||
| Color-change diasporeEnglish | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
| CsariteEnglish | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited); Note: Brand / trade name. |
| ZultaniteEnglish | market name | matched automatically | no restriction recorded | editorial ruling (no clause cited); Note: Brand / trade name. |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- ダイアスポア (not yet checked for this body — the entry's own Japanese name is shown)
- Mineral / material name (not in GB/T 16552 Annex A; usable directly)
- 硬水铝石 (GB/T 16552—2017 §5.1.1 b))
- Mineralogical name
- Diaspore (IMA mineral species); gem variety known as Zultanite® or Csarite®
- Trade names and synonyms
- Zultanite (market name) · Csarite (market name) · Color-change diaspore (market name)
Four-language names
- 简体中文
- 硬水铝石
- 繁體中文
- 硬水鋁石
- English
- Diaspore
- 日本語
- ダイアスポア
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural inorganic gem materials
- Browsing family
- Oxide minerals
- Identity tier
- Mineral species
- Mineral chemical class
- Oxides / hydroxides
- Construction or treatment status
- Natural identity; treatment status unknown
What it is and how it's identified
The registered material facts for Diaspore are as follows. Its nomenclature status is IMA status G, grandfathered: described before the IMA existed and generally regarded as a valid species. Its composition (phase) is recorded as diaspore, and its Mohs hardness is 6.5–7. Untreated Diaspore has perfect cleavage and is very brittle. Transparency is recorded as transparent to translucent. The body colour of untreated Diaspore is greenish brown, yellow or colourless, sometimes pink or white, with this site's qualification that the colour descriptions of entries such as smithsonite, amblygonite and danburite in chapter 7 of the CIBJO Gemmological Laboratories Book also mention brown or brownish tones. The optical effect is recorded as colour change, with this site's qualification that the cited source says a colour-change effect may occur.
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
Diaspore — 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
Diaspore — composition (phase): diaspore
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Durability
Diaspore — Mohs hardness: 6.5–7
Handbook of Mineralogy
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))
Source & check 2026-09-20
- Source
- Handbook of Mineralogy — Diaspore (Mineral Data Publishing): p. 1, Physical Properties (locator checked 2026-09-20)
- Fact checked on
- 2026-09-20
Diaspore — toughness: cleavage perfect; tenacity very brittle
Handbook of Mineralogy
- Treatment state
- untreated
Source & check 2026-09-20
- Source
- Handbook of Mineralogy — Diaspore (Mineral Data Publishing): p. 1, Physical Properties (locator checked 2026-09-20)
- Fact checked on
- 2026-09-20
Optical
Diaspore — transparency: transparent, translucent.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Diaspore — optical effect (colour change): colour change.
CIBJO Gemmological Laboratories Book 2024
- Qualification
The cited source states that this effect may occur.
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Diaspore — body colour: greenish-brown, yellow, colourless, sometimes pink or white.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Smithsonite, Amblygonite, Datolite and other entries also name brown or a brownish colour.
- General note
- colour alone is not identity
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
- CIBJO definitions
- colour change
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Testing and market
The tests the CIBJO laboratory protocol requires for Diaspore, and what each method means, are given in the protocol table on the laboratory testing page. The CIBJO laboratory protocol's note on test methods for Diaspore is that the special optical effect is colour change, and colour is judged by the colour-change effect. According to the Diaspore record in the CIBJO Official Gemstone Book 2022, there is no synthetic Diaspore 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: §6.1.24.
How far testing can go
Diaspore — 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
Diaspore — notes on test methods in the CIBJO laboratory protocol:
| Test method | What the protocol notes for it |
|---|---|
| Phenomena: | Colour-change; |
| Colour call: | Colour change |
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
Diaspore is defined directly in the CIBJO Gemmological Laboratories Book 2024, under the term Diaspore, as greenish brown, yellow, colourless, sometimes pink or white, and transparent or translucent. The cross-check result is defined directly by CIBJO, with no English term of the same name found directly in the GB/T annex of this edition.
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| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Diaspore | 7.2.1.73 | greenish-brown, yellow, colourless, sometimes pink or white; transparent, translucent. May show a colour change from greenish in daylight to pinkish brown under incandescent light | Defined directly by CIBJO; no identically named English entry was found in this edition of the GB/T annex. |
Evidence and sources
Authority basis and clause sources
Sources
- 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 | Oxide minerals | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Diaspore 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.