Chromite
Mouat-Sampson Mine, Stillwater County, Montana, USA
7.5 x 6.8 x 2.8 cm. A dense, solid mass of microcrystalline (1 mm) chromite. The black crystals have superb luster, causing the piece to have the appearance of black schist. This chromite is typical for the Stillwater Complex, a well-known Pt-Pd deposit.
© Rob Lavinsky & irocks.com