Linarite - PbCuSO₄(OH)₂

Habit: Bright to dark azure blue. Crystals elongated, typically tabular; crusts and aggregates. Vitreous to subadamantine luster; transparent to translucent. Light blue streak.

Environment: An uncommon secondary mineral in the oxidized zone of lead/copper deposits.

Etymology: From its occurrence at Linares, in Spain.