First occurrence of the mineral osakaite Zn4(OH)6(SO4)•5H2O for Bulgaria

Osakaite, a new mineral for Bulgaria, was discovered in stalactites from the Gyudyurska mine, South Petrovitsa deposit, South Rhodope. The chemical composition determines isomorphous inclusion of Cu2+ and composition (Zn3Cu)(OH)6(SO4)•5H2O. The mineral is a product of the interaction of mine waters passing through Zn and Cu-sulfide ores. During prolonged storage in atmospheric conditions, part of the osakaite crystals were dehydrated to the formation of the minerals namuwite Zn3Cu(OH)6(SO4)•4H2O and lahnsteinite Zn3Cu(OH)6(SO4)•3H2O.