noun
definition
A black mineral that is a mixed iron and manganese niobate and tantalate, and is the main ore of niobium and tantalum.
Examples of columbite in a Sentence
Columbium compounds are usually prepared by fusing columbite with an excess of acid potassium sulphate, boiling out the fused mass with much water, and removing tin and tungsten from the residue by digestion with ammonium sulphide, any iron present being simultaneously converted into ferrous sulphide.
It is usually found associated with tantalum, the chief minerals containing these two elements being tantalite, columbite, fergusonite and yttrotantalite; it is also a constituent of pyrochlor, euxenite and samarskite.
There were then neither dioceses nor parishes in Ireland and Celtic Scotland; and by the Columbite rule the bishops themselves, although they ordained the clergy, were subject to the jurisdiction of the abbots of Iona, who, like the founder of the order, were only presbyters.
Columbium pentoxide (columbic acid), Cb205, is obtained from columbite, after the removal of tantalum (see above).