THE MINERAL SKUTTERUDITE
- Chemistry: CoAs3, Cobalt Arsenide
- Class: Sulfides
- Uses: a minor ore of Cobalt and Nickel
Fine Skutterudite specimens have only recently had widespread distribution on the mineral market.
Its pyrite-like crystal forms contrast with its silver color giving it a unique look that is a must for a serious mineral collector.
Skutterudite is the cobalt-rich end member of a series (Smaltite, Chloanthite, or Ferro-Arsenite) in which Nickel or Iron replaces part of the Cobalt. Enough nickel is usually present to make Skutterudite a significant ore of Nickel. The iron rich variety is rare.
- Color is tin white to silver.
- Luster is metallic.
- Transparency crystals are opaque.
- Crystal System is isometric; bar 3 2/m
- Crystal Habits include the octahedron often modified with cube faces and the pyritohedron; often in a massive form.
- Cleavage is indistinct.
- Fracture is conchoidal or uneven.
- Hardness is 6.
- Specific Gravity is approximately 6.5 - 6.8 (heavier than average for metallic minerals)
- Streak is black.
- Associated Minerals are erythrite and annabergite which form weathering crusts; also other cobalt and nickel sulfides and arsenides such as cobaltite.
- Other Characteristics: sometimes irridescent.
- Notable Occurances include Cobalt, Ontario; Skutterud, Norway; Franklin, New Jersey and other cobalt mines around the world.
- Best Field Indicators are crystal habit, color, streak, lack of good cleavage and associations.