Galena PbS
Galena PbS. Crystal Data: Cubic. Point Group: 4/m 3 2/m. Most commonly cubic, crystals to a meter on an edge are known; more rarely cubo-octahedral or octahedral. May be tabular on {001}; also forms reticulated masses and skeletal crystals. As cleavable masses, coarse to very fine granular; fibrous, plumose. Twinning: Twin plane {111}, as both ...