1) Columbite-tantalite 2) Mineral 3) Oxide mineral
Found on
https://www.crosswordclues.com/clue/coltan
Coltan (short for columbite–tantalite and known industrially as tantalite) is a dull black metallic ore from which the elements niobium and tantalum are extracted. The niobium-dominant mineral in coltan is columbite (after niobium`s original American name, columbium), and the tantalum-dominant mineral is tantalite. Tantalum from coltan is used ....
Found on
http://en.wikipedia.org/wiki/Coltan
No exact match found.
