Euchroite

Euchroite is a hydrated copper arsenate hydroxide mineral with formula: Cu₂AsO₄OH·3H₂O. It is a vitreous green to emerald green mineral crystallizing in the orthorhombic system. It has a Mohs hardness of 3.5 - 4.0 and a specific gravity of 3.39 - 3.45. It was first described in 1823 in Ľubietová, Slovakia.