Multiple oxide containing niobium, columbite group
Specific gravity: 5.17
Streak: Dark brown
Colour: Black to brownish black, in fine splinters translucent brownish red, in transmitted light brown to reddish brown
At the type locality, the Muzeinaya pegmatite vein, Pyandzh River Valley, Gorno-Badakhshan, Tajikistan, columbite-(Mg) occurs in the pegmatite, in dolomitic marbles which have been partly assimilated with the formation of cordierite, dravite, spinel, andalasite, kyanite and others. The columbite-(Mg) occurs as acicular and tabular crystals 1 to 2 mm in size, with rough surfaces, and it is commonly intergrown with ilmenorutile (AM 48.1178-1184).
Back to Minerals