Plancheite, basic copper silicate,
Formula Cu8Si8O22(OH)2.H 2O

Crystal system: Orthorhombic
Hardness: 5.5
Density: 3.7 gms/cm3
Colour: Blue or blue-green
Streak: Light blue

Plancheite is a rare, translucent copper silicate occurring as a secondary mineral in oxydation zones. It forms as radial groups of needle-like or fibrous crystals. Plancheite is named after J. Planche who brought samples of the mineral back from Africa.

This specimen of Plancheite comes from M'sesa, Katanga, Zaire.

Plancheite crystals from M'sesa, Katanga, Zaire