The facts
What dioptase actually is
Mineralogically, dioptase is dioptase — CuSiO₃·H₂O, crystallising in the trigonal system.
The colour is caused by cu²⁺ in octahedral coordination. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.644–1.709, and the specific gravity sits near 3.28–3.35; cleavage is perfect rhombohedral {1011}.
Where dioptase comes from
The recognised sources are Tsumeb, Oshikoto, Namibia, Altyn-Tyube, Karaganda, Kazakhstan, Mindouli and Renéville, Republic of the Congo and Christmas Mine, Arizona, USA.
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 dioptase is treated
Untreated. An emerald-green that rivals emerald itself, undone by perfect cleavage in three directions and a hardness of 5 — it is a specimen mineral that is occasionally faceted for collectors and almost never set. Historically mistaken for emerald at Altyn-Tyube.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What dioptase is confused with
The usual confusions are Emerald, Malachite, Chrome diopside, Green tourmaline and Uvarovite.
The separation is rarely a matter of opinion: refractive index 1.644–1.709 and specific gravity 3.28–3.35 settle most of it in a minute, and magnification settles the rest.
What dioptase is used for
Dioptase is bought by mineral collecting, decorative objects and jewellery — 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 specimen, by the piece or by the carat.
Durability and care
Hardness 5; cleavage perfect rhombohedral {1011}. 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 dioptase costs
Indicative pricing for dioptase is Specimen pricing; faceted stones $100–1,000/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 dioptase treated, and how?
Untreated. An emerald-green that rivals emerald itself, undone by perfect cleavage in three directions and a hardness of 5 — it is a specimen mineral that is occasionally faceted for collectors and almost never set. Historically mistaken for emerald at Altyn-Tyube.
Where does dioptase come from?
Tsumeb, Oshikoto, Namibia, Altyn-Tyube, Karaganda, Kazakhstan, Mindouli and Renéville, Republic of the Congo and Christmas Mine, Arizona, USA. Origin affects price, so we name the locality rather than the country on every quote.
Is dioptase hard enough to wear every day?
Not really. At 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 dioptase cost?
Indicatively Specimen pricing; faceted stones $100–1,000/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 dioptase confused with?
Most often Emerald, Malachite, Chrome diopside, Green tourmaline and Uvarovite. A refractive index of 1.644–1.709 and a specific gravity near 3.28–3.35 separate it quickly.
What is dioptase used for besides jewellery?
mineral collecting and decorative objects. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for dioptase?
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 dioptase