The facts
What gypsum actually is
Gypsum is classified as gypsum, with the composition CaSO₄·2H₂O. It crystallises in the monoclinic system.
Colour comes from colourless and transparent when pure; sand and clay inclusions give the amber and brown of desert roses, which is also what a laboratory looks at when it is asked whether a colour is natural.
Refractive index 1.519–1.530. Specific gravity around 2.30–2.33. Cleavage: perfect {010}, distinct {100} and {011}. Those three numbers separate it from most of what imitates it.
Where gypsum comes from
Gypsum is produced at Naica (Cueva de los Cristales), Chihuahua, Mexico, Cave of the Swords, Naica, Mexico, Nottinghamshire and Cumbria, England (satin spar) and Ellsworth, Ohio, USA.
The locality is part of the description, not a footnote — two stones of the same weight from two of these places are not the same stone.
How gypsum is treated
Untreated, but the Mohs 2 hardness is the whole story: selenite scratches with a fingernail, dissolves slowly in water, and 'selenite' lamps and charging plates sold for wellness are simply satin-spar gypsum. Never wash gypsum. Some 'desert roses' are barite rather than gypsum.
Treatment changes value, sometimes by a multiple, so it belongs in the description before the price and not after the sale.
What gypsum is confused with
In the trade gypsum is most often mistaken for, or substituted by, Calcite, Barite desert rose, Anhydrite or Glass.
The separation is rarely a matter of opinion: refractive index 1.519–1.530 and specific gravity 2.30–2.33 settle most of it in a minute, and magnification settles the rest.
What gypsum is used for
Demand for gypsum comes from mineral collecting, carving and sculpture, decorative objects, architecture and interiors, wellness and body care and heavy industry, which is why one price per carat never covers it.
We quote each application in the unit that trade actually buys in, by the specimen, by the block or by the piece.
Durability and care
Hardness 2; cleavage perfect {010}, distinct {100} and {011}. That combination decides what it can safely be set into.
Below about 5.5 a stone will be scratched by ordinary household dust, which is largely quartz. That does not make it unusable — it makes it a pendant, an earring or an object rather than a ring worn every day.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What gypsum costs
As a guide, gypsum trades around Satin spar wands and plates $3–$40; fine selenite crystals $20–$1,000.
That is a range, not a quote. Colour, size, clarity, cut and origin move the figure a long way inside it, and the only honest price is one given against a specific stone. Send us what you need and we will price it.
Questions
Is gypsum treated, and how?
Untreated, but the Mohs 2 hardness is the whole story: selenite scratches with a fingernail, dissolves slowly in water, and 'selenite' lamps and charging plates sold for wellness are simply satin-spar gypsum. Never wash gypsum. Some 'desert roses' are barite rather than gypsum.
Where does gypsum come from?
Naica (Cueva de los Cristales), Chihuahua, Mexico, Cave of the Swords, Naica, Mexico, Nottinghamshire and Cumbria, England (satin spar) and Ellsworth, Ohio, USA. Origin affects price, so we name the locality rather than the country on every quote.
Is gypsum hard enough to wear every day?
Not really. At 2 on the Mohs scale it is softer than the quartz dust in ordinary household dirt, so it scratches with wear. It suits pendants, earrings and objects better than a daily ring.
How much does gypsum cost?
Indicatively Satin spar wands and plates $3–$40; fine selenite crystals $20–$1,000. Colour, size, clarity and origin move the price a long way within that, so treat it as a range and ask for a quote against a specific stone.
What is gypsum confused with?
Most often Calcite, Barite desert rose, Anhydrite and Glass. A refractive index of 1.519–1.530 and a specific gravity near 2.30–2.33 separate it quickly.
What is gypsum used for besides jewellery?
mineral collecting, carving and sculpture, decorative objects, architecture and interiors, wellness and body care and heavy industry. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for gypsum?
Tell us the size, the quality and what it is for. We source it, photograph it and quote it — with the locality named.
Ask about gypsum