The facts
What stibiotantalite actually is
Stibiotantalite is classified as antimony tantalate, with the composition SbTaO₄. It crystallises in the orthorhombic system.
Colour comes from sb and Ta give honey-brown to reddish and greenish brown; very high refractive index and dispersion, which is also what a laboratory looks at when it is asked whether a colour is natural.
Refractive index 2.37–2.45. Specific gravity around 7.20–7.90. Cleavage: distinct in one direction. Those three numbers separate it from most of what imitates it.
Where stibiotantalite comes from
Stibiotantalite is produced at Muiâne pegmatite, Zambezia, Mozambique, Mesa Grande, San Diego County, California, USA and Ratnapura, Sri Lanka.
The locality is part of the description, not a footnote — two stones of the same weight from two of these places are not the same stone.
How stibiotantalite is treated
Untreated. A high-lustre rarity: refractive index above diamond's range on a standard refractometer, so it reads over the limit.
Treatment changes value, sometimes by a multiple, so it belongs in the description before the price and not after the sale.
What stibiotantalite is confused with
In the trade stibiotantalite is most often mistaken for, or substituted by, Sphene, Cassiterite, Zircon or Rutile.
The separation is rarely a matter of opinion: refractive index 2.37–2.45 and specific gravity 7.20–7.90 settle most of it in a minute, and magnification settles the rest.
What stibiotantalite is used for
Demand for stibiotantalite comes from mineral collecting, which is why one price per carat never covers it.
We quote each application in the unit that trade actually buys in, by the specimen.
Durability and care
Stibiotantalite is 5.5–6 on the Mohs scale, with distinct in one direction cleavage.
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 stibiotantalite costs
As a guide, stibiotantalite trades around Faceted stones 200–1,000 USD/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 stibiotantalite treated, and how?
Untreated. A high-lustre rarity: refractive index above diamond's range on a standard refractometer, so it reads over the limit.
Where does stibiotantalite come from?
Muiâne pegmatite, Zambezia, Mozambique, Mesa Grande, San Diego County, California, USA and Ratnapura, Sri Lanka. Origin affects price, so we name the locality rather than the country on every quote.
Is stibiotantalite hard enough to wear every day?
Yes. At 5.5–6 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 stibiotantalite cost?
Indicatively Faceted stones 200–1,000 USD/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 stibiotantalite confused with?
Most often Sphene, Cassiterite, Zircon and Rutile. A refractive index of 2.37–2.45 and a specific gravity near 7.20–7.90 separate it quickly.
Related stones
Looking for stibiotantalite?
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 stibiotantalite