The facts
What diaspore actually is
The species behind diaspore is diaspore, AlO(OH); it forms in the orthorhombic system.
Traces of Fe, Mn and Cr producing a split transmission window, so the stone shifts from kiwi-green in daylight to champagne-pink under incandescent light is responsible for the colour — and the chromophore, not the name, is what decides whether a colour is stable.
On the instruments it reads a refractive index of 1.702–1.750 and a specific gravity of about 3.30–3.39, with perfect {010} cleavage.
Where diaspore comes from
Commercial material comes from İlbir Mountains, Milas, Muğla, Turkey, Chester, Massachusetts, USA and Mramorsk, Ural Mountains, Russia.
Different localities give different colour and different clarity, and the trade prices them differently. We state which one.
How diaspore is treated
Untreated — the colour change is natural, which the Turkish producers rightly emphasise. The perfect cleavage makes cutting risky and yields low, which is the real reason for the price. Beware synthetic colour-change corundum sold under the same trade names.
We state the treatment on every stone, including when the honest answer is that it cannot be determined. A treatment disclosed is a fact; a treatment discovered later is a refund.
What diaspore is confused with
Watch for Colour-change garnet, Alexandrite, Andalusite and Colour-change synthetic sapphire — these are what turn up sold under this name.
The separation is rarely a matter of opinion: refractive index 1.702–1.750 and specific gravity 3.30–3.39 settle most of it in a minute, and magnification settles the rest.
What diaspore is used for
The trades that buy diaspore are jewellery and mineral collecting. They do not want the same thing, and they do not pay in the same unit.
We quote each application in the unit that trade actually buys in, by the carat or by the specimen.
Durability and care
Hardness 6.5–7; cleavage perfect {010}. That combination decides what it can safely be set into.
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 diaspore costs
Expect roughly $100–$600/ct; large clean stones over 5 ct $500–$1,200/ct, depending on quality.
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 diaspore treated, and how?
Untreated — the colour change is natural, which the Turkish producers rightly emphasise. The perfect cleavage makes cutting risky and yields low, which is the real reason for the price. Beware synthetic colour-change corundum sold under the same trade names.
Where does diaspore come from?
İlbir Mountains, Milas, Muğla, Turkey, Chester, Massachusetts, USA and Mramorsk, Ural Mountains, Russia. Origin affects price, so we name the locality rather than the country on every quote.
Is diaspore hard enough to wear every day?
With care. It is 6.5–7 on the Mohs scale, which is hard enough, but perfect {010} cleavage means it can split if struck at the wrong angle. Use a protective setting and avoid ultrasonic cleaning.
How much does diaspore cost?
Indicatively $100–$600/ct; large clean stones over 5 ct $500–$1,200/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 diaspore confused with?
Most often Colour-change garnet, Alexandrite, Andalusite and Colour-change synthetic sapphire. A refractive index of 1.702–1.750 and a specific gravity near 3.30–3.39 separate it quickly.
Related stones
Looking for diaspore?
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 diaspore