Ixiolite Crystal With Cleavelandite
Helen Beryl Mine, Fourmile, Custer County, South Dakota, USA
Thumbnail, 2.2 x 1.7 x 1.3 cm
Ex. Thomas Campbell

Exceptional example of this rare, complex tantalum oxide. Black-brown, blocky, pseudo-orthorhombic, prismatic crystal of ixiolite associated with pinkish (iron-stained) albite, var. cleavelandite. The crystal is terminated and displays two complete and one partially exposed prism faces with the other prism and lower termination intergrown with albite. Thomas and Melissa Campbell collection