The facts
What moonstone actually is
Mineralogically, moonstone is orthoclase / albite feldspar — KAlSi₃O₈, crystallising in the monoclinic system.
The colour is caused by adularescence from alternating feldspar lamellae. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.518–1.526, and the specific gravity sits near 2.56–2.59; cleavage is perfect, two directions.
Where moonstone comes from
The recognised sources are Meetiyagoda, Sri Lanka, India, Madagascar and Myanmar.
Origin affects price in this material, so we name the locality on every quote rather than the country. "African" or "Asian" tells a buyer nothing.
Is moonstone treated?
None normally. Backed and assembled imitations exist.
Nothing needs disclosing, and nothing about the stone can change after you buy it. If a price looks impossible, the risk is substitution rather than treatment.
What moonstone is confused with
The usual confusions are Chalcedony, Opalite glass and Synthetic spinel.
The separation is rarely a matter of opinion: refractive index 1.518–1.526 and specific gravity 2.56–2.59 settle most of it in a minute, and magnification settles the rest.
What moonstone is used for
Moonstone is bought by jewellery, watch dials and wellness and body care — and each of those trades wants a different form of the same material.
We quote each application in the unit that trade actually buys in, by the carat, by the disc or by the kilo.
Durability and care
Moonstone is 6–6.5 on the Mohs scale, with perfect, two directions cleavage.
Hardness is not the whole story. Perfect cleavage means the stone can split cleanly if struck along the wrong plane, whatever its Mohs number, so a protective setting matters more here than the hardness suggests.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What moonstone costs
Indicative pricing for moonstone is $2–150/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 moonstone treated?
None normally. Backed and assembled imitations exist.
Where does moonstone come from?
Meetiyagoda, Sri Lanka, India, Madagascar and Myanmar. Origin affects price, so we name the locality rather than the country on every quote.
Is moonstone hard enough to wear every day?
With care. It is 6–6.5 on the Mohs scale, which is hard enough, but perfect, two directions cleavage means it can split if struck at the wrong angle. Use a protective setting and avoid ultrasonic cleaning.
How much does moonstone cost?
Indicatively $2–150/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 moonstone confused with?
Most often Chalcedony, Opalite glass and Synthetic spinel. A refractive index of 1.518–1.526 and a specific gravity near 2.56–2.59 separate it quickly.
What is moonstone used for besides jewellery?
watch dials and wellness and body care. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for moonstone?
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 moonstone