It is a copper aluminum [[phosphate]] with the chemical composition: CuAl<sub>6</sub>(PO<sub>4</sub>)<sub>4</sub>(OH)<sub>8</sub>·4H<sub>2</sub>O. It has a [[hardness]] rating of 5 - 6 on the [[Mohs Hardness Scale|Mohs scale]], and a specific Gravity of around 2.6 - 2.8. | It is a copper aluminum [[phosphate]] with the chemical composition: CuAl<sub>6</sub>(PO<sub>4</sub>)<sub>4</sub>(OH)<sub>8</sub>·4H<sub>2</sub>O. It has a [[hardness]] rating of 5 - 6 on the [[Mohs Hardness Scale|Mohs scale]], and a specific Gravity of around 2.6 - 2.8. |