Dolomite

Field of view: 40 mm. A vein of dolomite. The white vein network is dolomite, and dark green part is the host serpentinite. Note that cleavage of dolomite is vertical to the vein wall. The yellow grain with a metallic luster at the left is arsenopyrite.

Recovered from a dolomite vein in serpentine of a Fe-Ni deposit in serpentinitized harzburgite, a part of an opholite.