Zn₂AsO₄(OH).H₂O

This sample of legrandite is displayed in the Smithsonian Museum of Natural History. Legrandite is a oxide mineral of zinc and arsenic (an arsenate) with the composition Zn₂AsO₄(OH).H₂O. The sample at left is about 18 cm across and is from Ojeula mine, Mapimi, Durango, Mexico. The inset gem is 3.4 caras and is from the same location.