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
Gypsum
Also known asAlabaster · Satin spar (conditional name) · Selenite (conditional name)
A hydrous calcium sulfate mineral species with the formula CaSO4·2H2O. It has extremely low hardness and does not tolerate water; jewelry mostly uses selenite or satin spar. 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.
Questions people ask about Gypsum
Every sentence below is followed by the registered fact it rests on; answers add no new facts and promise no outcome.
Q1Is selenite the same as gypsum?
Yes: selenite is the crystalline form of gypsum.NPS White SandsGypsum is hydrous calcium sulfate, CaSO4.2H2O, and the most common sulfate mineral.Handbook of Mineralogy
Q2Can selenite get wet?
Water is a risk: gypsum dissolves in water and recrystallises as the water evaporates, much like salt.NPS White SandsA mineral-conservation database records gypsum as slightly soluble in water.Mineral Sensitivity Database, Oxford (2021)CIBJO advises against ultrasonic cleaning.CIBJO Gemstone Book 2022
Q3Why does selenite break and scratch so easily?
The US National Park Service describes selenite crystals as very brittle and fragile.NPS White SandsIts hardness is recorded as only 1.5–2, varying with direction.Handbook of MineralogyIt has perfect cleavage and is flexible but not elastic.Handbook of MineralogyCIBJO notes that its low hardness makes it scratch easily and that it cleaves or fractures easily, so it should be worn with care.CIBJO Gemstone Book 2022
Q4Is alabaster the same as gypsum?
Sometimes: some museum objects are catalogued as gypsum alabaster, such as a Cypriot flask in The Met labelled 'Gypsum (alabaster)'.The Met 38.40.372 · The Met 64.61 +6But not all alabaster is gypsum: one vessel is explicitly 'calcite alabaster', the calcite variety often called Egyptian alabaster, and many objects labelled only 'alabaster' leave the mineral unnamed.The Met 38.40.372 · The Met 64.61 +6
Q5What colours and lustre does gypsum have?
Gypsum is typically colourless to white, and impurities can make it yellow, tan, blue, pink, brown, reddish brown, grey or black.Handbook of MineralogyIts lustre is subvitreous, pearly on its main cleavage, and silky when fibrous.Handbook of Mineralogy
Q6How does gypsum form?
Gypsum is common in sedimentary rocks, especially marine salt deposits, and in soils; it forms directly by evaporation or later from anhydrite taking up water, and also where sulfuric acid meets carbonate rock or volcanic sulfur gases act on calcium-bearing rock.Handbook of Mineralogy
Q7Does selenite have cleansing or healing powers?
There is no scientific evidence that selenite has healing powers: the UK advertising regulators ASA and CAP state that they have not seen evidence that crystal therapy can treat medical conditions.ASA/CAP guidance (UK)
Sources cited in these answers ASA/CAP guidance (UK)
What this page can answer
This page covers
- How Gypsum 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 GypsumHow far lab testing can go and whether a synthetic exists
- Caring for and wearing GypsumCleaning, heat, chemicals and light, as the cited sources give them; durability indicators and wearing advice
- Hardness of GypsumEach value with its source and check date
- Gypsum 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 GypsumWhere the name comes from; how people have used it, with museum objects
- Listing and disclosing GypsumThe listing name to use; what must be disclosed before sale
- Standard clauses that define GypsumWhich 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
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.
Gypsum is a hydrous calcium sulfate mineral, formula CaSO4.2H2O, and the most common sulfate mineral. It is a frequent component of sedimentary rocks — especially marine salt deposits — and of soils. It forms either directly through evaporation or later through hydration of anhydrite; it also arises where sulfuric acid meets carbonate rock in oxidizing sulfide deposits and where sulfurous volcanic gases act on surrounding calcium-bearing rock, and it appears as efflorescences in mines and as speleothems in caves. Gypsum is monoclinic and very soft, its crystals typically tabular with swallow-tail twins and perfect {010} cleavage.
Scope: Applies to the genesis, occurrence, composition and appearance of natural gypsum as a mineral species; does not cover industrially processed products such as calcined gypsum (plaster of Paris).
Sources Handbook of Mineralogy
Where it forms
Marine salt deposits, together with soils; the mineral forms through direct evaporation or, later, through hydration of anhydrite.
Sources Handbook of Mineralogy
Where sulfuric acid reacts with carbonate rock within oxidizing sulfide deposits.
Sources Handbook of Mineralogy
By sulfurous volcanic gases acting on Ca-bearing rock; as mine efflorescences and cave speleothems
Sources Handbook of Mineralogy
How it forms, step by step
In evaporative settings, calcium sulfate-bearing brines concentrate and precipitate gypsum directly, or anhydrite first.
Sources Handbook of Mineralogy
Anhydrite later hydrates to gypsum (CaSO4.2H2O).
Sources Handbook of Mineralogy
In oxidizing sulfide deposits or volcanic settings, sulfuric acid reacts with Ca-bearing rock, or sulfurous gases act to form gypsum.
Sources Handbook of Mineralogy
Link to appearance
Gypsum is mostly colorless to white, and if colored by impurities may be yellow, tan, blue, pink, brown, reddish brown, gray, or black; it has a subvitreous luster, is pearly on {010} cleavages, and silky if fibrous. Its hardness is very low (about 1.5-2) with perfect {010} cleavage, and crystals are typically tabular, developing swallow-tail, V-shaped, or butterfly twins.
Sources Handbook of Mineralogy
Timescale
The source states no absolute geological timescale for gypsum formation.
Sources Handbook of Mineralogy
Supporting findings
Gypsum is a frequent component of sedimentary rocks — especially marine salt deposits — and of soils. It forms either directly through evaporation or later through hydration of anhydrite; it also arises where sulfuric acid meets carbonate rock in oxidizing sulfide deposits and where sulfurous volcanic gases act on surrounding calcium-bearing rock, and it appears as efflorescences in mines and as speleothems in caves.
Evidence grade BScope: Describes gypsum's several natural formation pathways.
Sources Handbook of Mineralogy
Gypsum is commonly associated with halite, celestine, calcite, aragonite, anhydrite, dolomite, and sulfur.
Evidence grade BScope: Describes gypsum's associations and occurrence context.
Sources Handbook of Mineralogy
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Asia
- Meskerabad, near Tehran, IranSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
Europe
- Racalmuto, Cianciana and Agrigento, Sicily, ItalySpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
- Eisleben–Mansfeld–Sangerhausen district, Saxony-Anhalt, GermanySpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
- near Königslutter, Lower Saxony, GermanySpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
- Bex, Valais, SwitzerlandSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
- Aussee, Styria, AustriaSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
- Hall, Tyrol, AustriaSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
- Zaragoza, Zaragoza Province, SpainSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
- Montmartre, Paris, FranceSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
- Tarnobrzeg, PolandSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
North America
- Naica Pb–Ag mine, Chihuahua, MexicoSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
- San Antonio mine, Santa Eulalia, Chihuahua, MexicoSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
- South Wash, Wayne County, Utah, United StatesSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
- Great Salt Plains, Alfalfa County, Oklahoma, United StatesSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
- Lechuguilla Cave, Carlsbad Caverns National Park, New Mexico, United StatesSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
South America
- El Teniente mine, O'Higgins Region, ChileSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
Sources Handbook of Mineralogy
Oceania
- Cloncurry, Queensland, AustraliaSpecimen/occurrence locality listed by the Handbook of Mineralogy; not a commercial gem source
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
Gypsum is typically colorless to white, and if colored by impurities may be yellow, tan, blue, pink, brown, reddish brown, gray, or black.
Evidence grade BScope: Describes gypsum's color and impurity coloring; the source lists no specific chromophore.
Sources Handbook of Mineralogy
Gypsum has a subvitreous luster, is pearly on {010} cleavages, and silky if fibrous, and its {010} cleavage is perfect.
Evidence grade BScope: Describes the relationship between gypsum's luster and cleavage.
Sources Handbook of Mineralogy
Where the name comes from
The name gypsum comes from a Greek term denoting plaster produced from calcined gypsum.
Evidence grade BScope: The etymology explains the origin of a name only; it does not attest composition, locality, naturalness or treatment.
Sources Handbook of Mineralogy
Human use and museum objects
The Met's Cypriot alabaster flask (74.51.5114, late 4th–3rd century BCE) is labelled 'Gypsum (alabaster)', its Iranian 12th–13th-century standing figure (67.119) 'Gypsum plaster', and a Syrian 8th-century capital (36.68.1) 'Alabaster, gypsum; carved'; these are the objects whose medium field explicitly names gypsum.
Evidence grade AScope: Based only on the museum's cataloguing of these specific objects; it is not generalized to widespread practice or universal use of the material.
Sources The Met 38.40.372 · The Met 64.61 · The Met 62.70.18 +5
- The Metropolitan Museum of Art — Stone vessel fragment (38.40.372)
- The Metropolitan Museum of Art — Vessel (64.61)
- The Metropolitan Museum of Art — Vessel (62.70.18)
- The Metropolitan Museum of Art — Alabaster flask (74.51.5114)
- The Metropolitan Museum of Art — Capital in the "Beveled Style" (36.68.1)
- The Metropolitan Museum of Art — Standing Figure with Jeweled Headdress (67.119)
- The Metropolitan Museum of Art — Vessel with a lid (1995.67.1a, b)
- Cleveland Museum of Art — Charity (1951.541)
Many museum objects are labelled only 'Alabaster', leaving the mineral unnamed, while one Southwestern-Arabian vessel (1995.67.1a, b, ca. mid-1st millennium BCE) is explicitly 'Calcite alabaster' (the calcite variety often called 'Egyptian alabaster'). Not all 'alabaster' objects in these collections should be treated as gypsum.
Evidence grade AScope: Based only on the museum's cataloguing of these specific objects; it is not generalized to widespread practice or universal use of the material.
Sources The Met 38.40.372 · The Met 64.61 · The Met 62.70.18 +5
- The Metropolitan Museum of Art — Stone vessel fragment (38.40.372)
- The Metropolitan Museum of Art — Vessel (64.61)
- The Metropolitan Museum of Art — Vessel (62.70.18)
- The Metropolitan Museum of Art — Alabaster flask (74.51.5114)
- The Metropolitan Museum of Art — Capital in the "Beveled Style" (36.68.1)
- The Metropolitan Museum of Art — Standing Figure with Jeweled Headdress (67.119)
- The Metropolitan Museum of Art — Vessel with a lid (1995.67.1a, b)
- Cleveland Museum of Art — Charity (1951.541)
The museum's medium fields use different wording and must be read as written rather than equated with gypsum. The Met's Cypriot alabaster flask (74.51.5114, late 4th–3rd century BCE) is labelled 'Gypsum (alabaster)', and its Iranian 12th–13th-century standing figure (67.119) 'Gypsum plaster'; a Syrian 8th-century 'Beveled Style' capital (36.68.1) reads 'Alabaster, gypsum; carved'. Many other vessels are labelled only 'Alabaster' (e.g. an Iranian Chalcolithic–Early Bronze Age stone vessel fragment 38.40.372, 5th–3rd millennium BCE; a Proto-Elamite vessel 64.61, ca. 3000 BCE; a Sumerian vessel 62.70.18, ca. 2700–2600 BCE; Cleveland 1951.541, second half 16th century), where the museum wording does not name the mineral; and one Southwestern-Arabian vessel (1995.67.1a, b, ca. mid-1st millennium BCE) is explicitly 'Calcite alabaster' — the calcite variety often called 'Egyptian alabaster', not gypsum. Only objects whose medium says gypsum serve as gypsum object evidence; pieces labelled merely 'Alabaster' cannot be assumed to be gypsum.
Sources The Met 38.40.372 · The Met 64.61 · The Met 62.70.18 +5
- The Metropolitan Museum of Art — Stone vessel fragment (38.40.372)
- The Metropolitan Museum of Art — Vessel (64.61)
- The Metropolitan Museum of Art — Vessel (62.70.18)
- The Metropolitan Museum of Art — Alabaster flask (74.51.5114)
- The Metropolitan Museum of Art — Capital in the "Beveled Style" (36.68.1)
- The Metropolitan Museum of Art — Standing Figure with Jeweled Headdress (67.119)
- The Metropolitan Museum of Art — Vessel with a lid (1995.67.1a, b)
- Cleveland Museum of Art — Charity (1951.541)
Scope: A museum object evidences only that artefact's existence and date; it does not establish widespread ancient use of the material, nor does it authenticate the origin, naturalness or treatment of any modern specimen.
Objects cited
- The Met 38.40.372Alabaster
- The Met 64.61Alabaster
- The Met 62.70.18Alabaster
- The Met 74.51.5114Gypsum (alabaster)
- The Met 36.68.1Alabaster, gypsum; carved
- The Met 67.119Gypsum plaster; modeled, carved, polychrome-painted, gilded
- The Met 1995.67.1a, bCalcite alabaster
- Cleveland Museum of Art 1951.541alabaster
Other research findings
Gypsum has the formula CaSO4.2H2O and is the most common sulfate mineral.
Evidence grade BScope: Concerns gypsum's composition and abundance status.
Sources Handbook of Mineralogy
Selenite is the crystalline form of gypsum. Gypsum dissolves in water and recrystallises as the water evaporates, much like salt. The US National Park Service describes selenite crystals as very brittle and fragile.
Evidence grade BScope: Reports mineral properties from a US federal agency page; it is not a care instruction for any particular piece. The trade also uses the name selenite loosely for fibrous satin spar, which is likewise a form of gypsum.
Sources NPS White Sands
A mineral-conservation database compiled at the University of Oxford records gypsum as slightly soluble in water.
Evidence grade BScope: A specimen-conservation reference on mineral sensitivities, not jewellery care advice.
Sources Mineral Sensitivity Database, Oxford (2021)
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The source states no absolute age or specific P-T conditions for gypsum formation.
- The source lists no specific chromophores for impurity coloration in gypsum.
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
- Gypsum
GB/T 16552—2017 5.1.1 b) · IMA Mineral List 2026-07 “Gypsum”
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
Gypsum is Gypsum (IMA mineral species, CaSO4·2H2O); use "Gypsum" for listings, and disclose any known treatments.
Evidence
- GB/T · 5.1.1 b)
What this means for you
Before buying, check the recommended listing name "Gypsum" 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
Gypsum — 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, Gypsum, p.56; §6.2 j (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
Gypsum — care (chemicals): Some stones are porous. Do not allow contact with coloured fluids.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code c
- 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, Gypsum, p.56; §6.2 c (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
Gypsum — care (chemicals): Treatments with dye, oil, resin, wax or plastic are not permanent; keep it away from all solvents (including dish-washing liquids), chemicals and heat.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code k
- Treatment state
- treated
Source & check 2026-09-25
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, Gypsum, p.56; §6.2 k (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
Gypsum — care (wear): low hardness, so it scratches easily; wear with care; 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 a, 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, Gypsum, p.56; §6.2 a, 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
The care conclusions for Gypsum come from the CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022). CleaningRegardless of treatment status, gypsum must not be cleaned ultrasonically; regardless of treatment status, gypsum is porous, so keep it away from coloured liquids. ChemicalsFor gypsum treated with dye, oil, resin, wax or plastic, the status is treated; these treatments are not permanent, so keep it away from all solvents (including dish-washing liquids), chemicals and heat. WearRegardless of treatment status, gypsum is soft, scratches easily and cleaves or fractures easily, so wear it with care.
This table scrolls sideways on narrow screens.
| Question | Matching entries |
|---|---|
| Can it go in an ultrasonic or steam cleaner? | care (cleaning) |
| Contact with acids, alkalis and household chemicals | care (chemicals); Treatments with dye, oil, resin, wax or plastic are not permanent; keep it away from all solvents (including dish-washing liquids), chemicals and heat |
| Wearing limits (knocks, settings) | low hardness, so it scratches easily; wear with care; cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care |
Care entries by treatment state
The same entries grouped by the treatment state each applies to; each links to its full wording and source. Letters are CIBJO special-care codes, explained on the gemstone care page.
any treatment state
- care (cleaning) §6.2 j
- care (chemicals) §6.2 c
- low hardness, so it scratches easily; wear with care; cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care §6.2 a, b
treated
Durability and wearing
Cleavage
{010} perfect; {100} distinct; {011} present
Fracture
Splintery along [001]; conchoidal on {100}
Sources Handbook of Mineralogy
VerifyNames, standards, technical facts, clauses and sources
Names
Besides Gypsum, the name register records "Alabaster", "Satin spar" and "Selenite", for which no restriction on use as a name is recorded (CIBJO Gemmological Laboratories Book 2024 §7.2.1.4 “Alabaster”).
Standard and listing namesGypsum is not listed in GB/T 16552—2017 Annex A, but can be named directly by its mineralogical name, gypsum, and the suggested listing name is Gypsum. Trade and mineralogical namesThe mineralogical name is Gypsum, with the chemical formula CaSO4·2H2O, and the IMA mineral list records it as Gypsum. Sub-names and unacceptable namesTrade names or synonyms include Selenite (the transparent variety) and Satin spar (the fibrous variety), and Alabaster is a sub-name (variety or sub-type). Japanese namesThe GSJ (Japan) formal name is gypsum, with alabaster noted. Names in four languagesNames are registered in four languages: Simplified Chinese, Traditional Chinese, English (Gypsum) and Japanese. Institution usageOn authority wording, CIBJO records Gypsum (CIBJO Gemmological Laboratories Book 2024); the FTC has been checked and its text on file has no wording for this name; the wording of GIA and Gem-A is not yet verified. Bodies without a recorded wording show the English name of Gypsum itself, which does not represent the position of those bodies.
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) | ||||
| AlabasterEnglish | narrower name (variety or subtype) | matched automatically | no restriction recorded | CIBJO Gemmological Laboratories Book 2024 §7.2.1.4 “Alabaster” |
| Satin sparEnglish | narrower name (variety or subtype) | matched only once the condition is confirmed | no restriction recorded | editorial ruling (no clause cited) |
| SeleniteEnglish | narrower name (variety or subtype) | matched only once the condition is confirmed | no restriction recorded | editorial ruling (no clause cited) |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- 石膏（雪花石膏）
- Mineral / material name (not in GB/T 16552 Annex A; usable directly)
- 石膏 (GB/T 16552—2017 §5.1.1 b))
- Mineralogical name
- Gypsum (IMA mineral species, CaSO4·2H2O)
- Trade names and synonyms
- Selenite (narrower name (variety or subtype); conditional name) · Satin spar (narrower name (variety or subtype); conditional name) · Alabaster (narrower name (variety or subtype))
Four-language names
- 简体中文
- 石膏
- 繁體中文
- 石膏
- English
- Gypsum
- 日本語
- 石膏／ジプサム
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural inorganic gem materials
- Browsing family
- Sulfate minerals
- Identity tier
- Mineral species
- Mineral chemical class
- Sulfates
- Construction or treatment status
- Natural identity; treatment status unknown
What it is and how it's identified
Among the registered material facts for Gypsum, the nomenclature status is IMA status G, grandfathered: described before the IMA existed and generally regarded as a valid species; the composition (phase) is gypsum. For durability, the Mohs hardness of Gypsum is 1.5–2, and the cited source states that this value varies with crystal direction; untreated, cleavage is perfect and tenacity flexible but not elastic. Optically, Gypsum is transparent to opaque; untreated, its body colour is colourless, white, yellowish, bluish or pink, and in chapter 7 of the CIBJO Gemmological Laboratories Book the colour descriptions of entries such as calcite, smithsonite and amblygonite also mention colourless.
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
Gypsum — 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
Gypsum — composition (phase): gypsum
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Durability
Gypsum — Mohs hardness: 1.5–2
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); Calcite 3, Quartz 7 (Source: Handbook of Mineralogy); Corundum 9 (Source: GIA Gem Encyclopedia (care guide))
- Qualification
The cited source states that the value varies with crystallographic direction.
Source & check 2026-09-20
- Source
- Handbook of Mineralogy — Gypsum (Mineral Data Publishing): p. 1, Physical Properties (locator checked 2026-09-20)
- Fact checked on
- 2026-09-20
Gypsum — toughness: cleavage perfect; tenacity flexible, inelastic
Handbook of Mineralogy
- Treatment state
- untreated
Source & check 2026-09-20
- Source
- Handbook of Mineralogy — Gypsum (Mineral Data Publishing): p. 1, Physical Properties (locator checked 2026-09-20)
- Fact checked on
- 2026-09-20
Optical
Gypsum — transparency: transparent to opaque.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Gypsum — body colour: Colourless, white, yellowish, bluish, pink.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Calcite, Smithsonite, Amblygonite 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
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Testing and market
Identification facts for Gypsum include: the CIBJO laboratory protocol calls for particular checks because the material is soft and cleaves easily; the protocol's note on test methods mentions special optical effects, fibrous gypsum (satin spar) and chatoyancy; and there is no synthetic Gypsum on the market. The tests the CIBJO laboratory protocol requires for Gypsum, 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: §6.1.39.
How far testing can go
Gypsum — 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
Gypsum — what the CIBJO laboratory protocol says to watch for: soft material, easy cleavage
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- any treatment state
Source & check 2026-09-26
- Source
- Fact checked on
- 2026-09-26
Gypsum — notes on test methods in the CIBJO laboratory protocol:
| Test method | What the protocol notes for it |
|---|---|
| Phenomena: | Satin spar, cat’s-eye |
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
Gypsum has direct definitions in the CIBJO Gemmological Laboratories Book 2024 under two terms, Alabaster and Gypsum. The Alabaster definition describes a massive, aggregate variety of gypsum, white or grey, possibly banded and patterned, translucent to opaque. The Gypsum definition gives the mineral species as gypsum, IMA status G, with the CIBJO wording quoted in full under Clause-level definitions on this page. For both Alabaster and Gypsum, the cross-check result is defined directly by CIBJO, with no English term of the same name found directly in the GB/T annex. The IMA mineral list includes an entry under Gypsum, reading Ca(SO4)(H2O)2 with a question mark after G, cross-checked against the RRUFF/IMA mineral list master table, from public-domain data.
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| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Alabaster | 7.2.1.4 | Massive, aggregate variety of gypsum. White, grey, may be banded and patterned; translucent to opaque | Defined directly by CIBJO; no identically named English entry was found in this edition of the GB/T annex. |
| Gypsum | 7.2.1.102 | Colourless, white, yellowish, bluish, pink, transparent to opaque | Defined directly by CIBJO; no identically named English entry was found in this edition of the GB/T annex. |
| Gypsum | IMA Mineral List entry | Gypsum Ca(SO4)(H2O)2 G ? | 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.
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 | Sulfate minerals | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Gypsum 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.