Hauerite is a very rare manganese sulfide, and this is an exceptionally large and sharp octahedron. It measures to almost 2 cm on edge and about an inch fully through the longest angle. The lighter than normal color makes this even more attractive (usually they are a more dull black in hue). 2.7 x 2 x 1.9 cm This Photo was Mindat.org Photo of the Day - 10th Oct 2008