The facts
What star sapphire actually is
Mineralogically, star sapphire is corundum — Al₂O₃, crystallising in the trigonal system.
The colour is caused by rutile needles in three directions produce the six-rayed star. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.762–1.770, and the specific gravity sits near 3.95–4.03; cleavage is none.
Where star sapphire comes from
The recognised sources are Sri Lanka, Myanmar, Thailand and Madagascar.
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.
How star sapphire is treated
Diffusion-induced stars exist and are a different product entirely.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What star sapphire is confused with
The usual confusions are Diffused star corundum, Star diopside and Synthetic star sapphire.
The separation is rarely a matter of opinion: refractive index 1.762–1.770 and specific gravity 3.95–4.03 settle most of it in a minute, and magnification settles the rest.
What star sapphire is used for
Star sapphire is bought by jewellery and mineral collecting — 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 or by the specimen.
Durability and care
Hardness 9; cleavage none. That combination decides what it can safely be set into.
With no cleavage plane to worry about, the practical limit is abrasion rather than breakage, and it takes daily wear well.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What star sapphire costs
Indicative pricing for star sapphire is $50–5,000/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 star sapphire treated, and how?
Diffusion-induced stars exist and are a different product entirely.
Where does star sapphire come from?
Sri Lanka, Myanmar, Thailand and Madagascar. Origin affects price, so we name the locality rather than the country on every quote.
Is star sapphire hard enough to wear every day?
Yes. At 9 on the Mohs scale with no cleavage plane, it handles daily wear well. The practical limit is gradual abrasion rather than chipping.
How much does star sapphire cost?
Indicatively $50–5,000/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 star sapphire confused with?
Most often Diffused star corundum, Star diopside and Synthetic star sapphire. A refractive index of 1.762–1.770 and a specific gravity near 3.95–4.03 separate it quickly.
Related stones
Looking for star sapphire?
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 star sapphire