What is Cobaltite?
Cobaltite is a metallic cobalt arsenic sulfide and an important cobalt-bearing ore, valued by collectors for bright crystals and its role in hydrothermal ore systems.
Mineralogy and structure
The reference formula is CoAsS. Cobaltite belongs to the sulfides and has a orthorhombic crystal system. Cobaltite has a cubic structure related to the pyrite group. Arsenic-bearing sulfides should be handled as display specimens and never ground or used for jewellery.
Colour and appearance
Typical colours include silver-white, steel-grey, pinkish grey. Crystal habit, lustre, transparency and matrix association are often as diagnostic as colour.
Formation and localities
Cobaltite forms in or is associated with hydrothermal veins, skarns and metamorphosed massive sulfide deposits. Important documented localities include Ontario in Canada, Sweden, Norway, Morocco and cobalt-rich mining districts worldwide.
Collecting and care
Cobaltite is best kept as a labelled collector or reference specimen. Protect fragile crystals from impact and prolonged humidity changes. Lead-, arsenic-, chromium- and cobalt-bearing minerals should not be cut, ground or used in jewellery.
