- Small Cabinet, 5.1 x 4.3 x 4.0 cm
- Robert Mine (Roberts Mine; Kennedy Mine), Cuyuna Range, Crow Wing Co., Minnesota, USA
Super-lustrous, jet-black groutite crystals richly line two larger vugs and smaller vugs in a very interesting quartz and massive manganese matrix from a mine near the Minnesota type locality. The box work quartz "cap" on the top of the piece is striking. This is a very fine specimen of the species from a famous lucky strike in the 1980s.