Andyrobertsite is a rare, complex arsenate mineral with a blue color. It is found in the Tsumeb mine in Namibia and named after Andrew C. Roberts (b. 1950), a mineralogist with the Geological Survey of Canada. A Ca-rich analog (with Ca instead of Cd) is called calcioandyrobertsite and has a more greenish tint.
General Information
- Category: Arsenate mineral
- Formula: KCdCu5(AsO4)4(H2AsO4)·2H2O
- Crystal system: Monoclinic
- Crystal class: Prismatic (2/m).
Properties
It looks electric blue with a pale-blue streak, a vitreous luster, and they do not fluoresce under longwave or shortwave ultraviolet light. The aggregate has a Mohs hardness of 3, is brittle with a conchoidal fracture, and has good cleavage parallel to (100).
- Color: Blue
- Crystal habit: Platy
- Mohs scale hardness: 3
- Luster: Vitreous
- Streak: Pale blue
- Diaphaneity: Transparent
- Specific gravity: 4.
Information Source:
