The facts
What celestine actually is
Celestine is classified as celestine, with the composition SrSO₄. It crystallises in the orthorhombic system.
Colour comes from pale sky-blue from colour centres created by natural irradiation, associated with sulphate radical defects; the colour can fade in strong light, which is also what a laboratory looks at when it is asked whether a colour is natural.
Refractive index 1.619–1.635. Specific gravity around 3.96–3.98. Cleavage: perfect {001}, good {210}. Those three numbers separate it from most of what imitates it.
Where celestine comes from
Celestine is produced at Put-in-Bay (Crystal Cave), South Bass Island, Ohio, USA, Sakoany and Mahajanga, Madagascar, Maybee, Michigan, USA and Cianciana, Sicily, Italy.
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 celestine is treated
Untreated, but the pale blue fades with prolonged light exposure, so geodes should be displayed away from windows. Some cheap 'celestite' geodes on the wellness market are dyed; genuine Madagascan colour is soft and slightly grey-blue, not electric.
Treatment changes value, sometimes by a multiple, so it belongs in the description before the price and not after the sale.
What celestine is confused with
In the trade celestine is most often mistaken for, or substituted by, Barite, Anhydrite, Aquamarine, Blue calcite or Dyed quartz geodes.
The separation is rarely a matter of opinion: refractive index 1.619–1.635 and specific gravity 3.96–3.98 settle most of it in a minute, and magnification settles the rest.
What celestine is used for
Demand for celestine comes from mineral collecting, 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 kilo or by the tonne.
Durability and care
Celestine is 3–3.5 on the Mohs scale, with perfect {001}, good {210} cleavage.
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 celestine costs
As a guide, celestine trades around Madagascan geodes $10–$400; fine Ohio crystals $100–$5,000; faceted stones $30–$120/ct.
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 celestine treated, and how?
Untreated, but the pale blue fades with prolonged light exposure, so geodes should be displayed away from windows. Some cheap 'celestite' geodes on the wellness market are dyed; genuine Madagascan colour is soft and slightly grey-blue, not electric.
Where does celestine come from?
Put-in-Bay (Crystal Cave), South Bass Island, Ohio, USA, Sakoany and Mahajanga, Madagascar, Maybee, Michigan, USA and Cianciana, Sicily, Italy. Origin affects price, so we name the locality rather than the country on every quote.
Is celestine hard enough to wear every day?
Not really. At 3–3.5 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 celestine cost?
Indicatively Madagascan geodes $10–$400; fine Ohio crystals $100–$5,000; faceted stones $30–$120/ct. 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 celestine confused with?
Most often Barite, Anhydrite, Aquamarine, Blue calcite and Dyed quartz geodes. A refractive index of 1.619–1.635 and a specific gravity near 3.96–3.98 separate it quickly.
What is celestine used for besides jewellery?
mineral collecting, 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 celestine?
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 celestine