Bismutotantalite
Bismutotantalite is a rare oxide mineral composed of bismuth and tantalum. It is known for its dark color, high density, and rarity. It is primarily valued as a collector’s mineral rather than a gemstone for jewelry.
About
Bismutotantalite
Bismutotantalite is a rare and complex oxide mineral with the chemical formula (Bi)(Ta,Nb)O₄, consisting mainly of bismuth and tantalum, sometimes with niobium substitution. It belongs to the oxide mineral group and crystallizes in the orthorhombic crystal system. Due to its unusual chemical composition and rarity, it is mainly of interest to mineral collectors and researchers rather than the commercial gemstone market. This mineral typically appears in colors such as black, dark brown, or gray, often with a submetallic to resinous luster. It is generally opaque, although thin edges may appear translucent. Well-formed crystals are uncommon, and the mineral is more frequently found in massive or granular forms.
Physical & Chemical Properties
| Name | Bismutotantalite |
|---|---|
| Scientific Name | Bismutotantalite |
| Mineral Group | Oxide |
| Hardness (Mohs) | 6 – 6.5 |
| Color | Black, dark brown, gray |
| Origin | Australia, Brazil, Namibia, Madagascar, USA |
| Chemical Formula | (Bi)(Ta,Nb)O₄ |
Quick Facts
| Crystal System | Orthorhombic |
|---|---|
| Specific Gravity | 7.5 – 8.2 |
| Birthstone | NA |
| Refractive Index | 2.2 – 2.3 |
| Optical Character | Anisotropic |
| Dispersion | Low |
| Major Sources | Australia, Brazil, Namibia, Madagascar, USA |
| Treatments | Bismutotantalite is typically untreated |
| Price Range | $20 – $100 |
| Care Instructions | Handle with care Avoid exposure to chemicals Clean with a soft cloth Store in a dry environment |