Tantalum
Sources. Tantalum is chiefly obtained as a by-product of tin processing, although it is also mined from the minerals columbite, tantalite and samarskite. Other tantalum-bearing minerals include ferrotantalite, manganotantalite and microlite. Tantalum and niobium are almost always found together, and are recovered from pegmatite veins in granite ...
