Mineral Species: Arsenopyrite

Chemical Formula: FeAsS

Chemical Name: Iron Arsenide Sulfide

Mineral Class: Sulphide

Mineral Notes: Arsenopyrite is a major ore of arsenic. The mineral can contain a small amount of gold as an impurity. Although an ore of arsenic, it is rarely mined for that reason. Instead, Arsenopyrite is a contaminant in other ores and arsenic is extracted as a byproduct of purification. The mineral often forms good crystals which have a distinct diamond dome on top of a prismatic crystal. The crystals have sharp acute angles that are a marked contrast from other sulfides that generally have only obtuse angles. 

Description: An irregular nugget of massive Arsenopyrite. Some crystal faces can be seen on the outside of the specimen. The mineral has a very unusual blue metallic sheen giving a very attractive effect.

Location: Great Condurrow Mine, Camborne, Cornwall, England.