Cobaltite
Species
Uncommon · CoAsS
Cobalt arsenic sulfide in silver white crystals shaped like pyrite's, from high-temperature veins and contact-metamorphic rocks; Tunaberg in Sweden gave fine crystals. Cobalt ores that resisted medieval smelting and gave off foul, poisonous fumes named the metal, from the goblin Kobold. Under the name sehta, cobaltite from Khetri gave Indian jewellers a blue enamel for gold and silver; it is still mined for cobalt.
Identity
- Formula
- CoAsS
- Chemical class
- Sulfide
- Also known as
- Sehta (India)
- Ore of
- Cobalt
Crystallography
- Crystal system
- Orthorhombic
- Habits
- Cubic, Octahedral, Granular, Massive
- Fracture
- Uneven
Physical properties
- Mohs hardness
- 5.5
- Density
- 6.33 g/cm³
- Luster
- Metallic
- Colors
- silver-white, pink
- Streak
- grayish black
- Transparency
- Opaque
Geology
- Origins
- Hydrothermal, Metamorphic
- Host rocks
- Granite, Marble
- Associated minerals
- Magnetite, Sphalerite, Chalcopyrite, Skutterudite, Scapolite, Zoisite, Calcite, Erythrite
- Found in
- Hydrothermal vein (lode), Skarn
- Geography
- Sweden (Tunaberg; Håkansboda; Vena), Norway (Skutterud, Modum), Germany (Siegen), England (Botallack, Cornwall), Canada (Cobalt, Ontario), India (Khetri, Rajasthan), Morocco (Bou Azzer)
Classification
- Rarity
- Uncommon
- Gem quality
- No
Sources
- M. Pasero and others, IMA Commission on New Minerals, Nomenclature and Classification, The New IMA List of Minerals, updated September 2026. International Mineralogical Association (CNMNC), 2026.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Cobaltite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Cobaltite. Wikipedia.
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