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.