- Small Cabinet, 7.5 x 6.7 x 4.2 cm
- Robert Mine (Roberts Mine; Kennedy Mine), Cuyuna Range, Crow Wing Co., Minnesota, USA
Super-lustrous, jet-black groutite crystals richly line a vug in a very interesting quartz and massive manganese matrix from a mine near the Minnesota type locality. This is a very fine specimen of the species from a famous lucky strike in the 1980s. Rare on the market!