The diverse conditions required to produce a different structure from the same chemistry are often so radically different that the minerals are not found together. What those exact conditions are, and how much they must change to produce the dimorph is of great interest to mineralogists and petrologists. Luster is vitreous. Crystals are transparent to translucent. Crystal Habits include rounded tabular crystals, usually aggregated.
Cleavage is perfect.
Fracture is uneven. Hardness is 3.5. Streak is white. Associated Minerals include adamite , legrandite , limonite , smithsonite , austinite , mimetite and other zinc oxidation zone minerals. Notable Occurrence is limited to the famous mines of Mapimi, Durango, Mexico .