The facts
What dumortierite actually is
The species behind dumortierite is dumortierite, Al₇BO₃(SiO₄)₃O₃; it forms in the orthorhombic system.
Iron and titanium 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 1.678–1.689 and a specific gravity of about 3.26–3.41, with good, one direction cleavage.
Where dumortierite comes from
Commercial material comes from Madagascar, Brazil, Namibia and Nevada, USA.
Different localities give different colour and different clarity, and the trade prices them differently. We state which one.
Is dumortierite treated?
None normally.
That makes disclosure simple: there is nothing to declare. It also means a seller offering a "treated" version of this material is offering something else.
What dumortierite is confused with
Watch for Lapis lazuli, Sodalite and Lazulite — these are what turn up sold under this name.
The separation is rarely a matter of opinion: refractive index 1.678–1.689 and specific gravity 3.26–3.41 settle most of it in a minute, and magnification settles the rest.
What dumortierite is used for
The trades that buy dumortierite are decorative objects, jewellery and ceramics. 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 piece or by the carat.
Durability and care
Hardness 7–8.5; cleavage good, one direction. 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 dumortierite costs
Expect roughly $0.50–15/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 dumortierite treated?
None normally.
Where does dumortierite come from?
Madagascar, Brazil, Namibia and Nevada, USA. Origin affects price, so we name the locality rather than the country on every quote.
Is dumortierite hard enough to wear every day?
Yes. At 7–8.5 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 dumortierite cost?
Indicatively $0.50–15/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 dumortierite confused with?
Most often Lapis lazuli, Sodalite and Lazulite. A refractive index of 1.678–1.689 and a specific gravity near 3.26–3.41 separate it quickly.
What is dumortierite used for besides jewellery?
decorative objects and ceramics. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for dumortierite?
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 dumortierite