The skutterudite Mineral Series
The Skutterudite series is a group of closely related arsenide
minerals with varying rates of cobalt, nickel, and sometimes iron. The cobalt-rich end member
is Skutterudite, and the nickel-rich end member is Nickelskutterudite
. Another, lesser-known mineral of this series is Ferroskutterudite
, a rare iron-rich member.
was originally described as an individual mineral species prior to 1987, after which it was discredited by the IMA
and merged into Nickelskutterudite. Smaltite
was the former name of the cobalt-rich end member, and this term has now been discredited by the IMA as well. Despite these terms being discredited, they are still occasionally used, and are especially seen on old labels. Smaltite may be used both as a synonym for Skutterudite, or to describe an intermediary
member with a similar cobalt and nickel content.
Although most Skutterudite is uninteresting in form, several localities have produced sharp, lustrous crystals that are striking in aesthetics. Skutterudite may partially alter
to pink Erythrite
, and Ferroskutterudite to green Annabergite
. Skutterudite is named after its type locality
of Skutterud, Norway.
[Arsenic may be slightly deficient in Nickelskutterudite, with a possible formula of (Ni,Co)As3-x]
5.5 - 6
6.4 - 6.9
Skutterudite is used as an ore of cobalt and nickel. Well-crystallized specimens are highly valued among collectors.
The Bou Azer District, Morocco, produces the best examples of Skutterudite, in large, lustrous crystals, often in a cuboctadral
shape. Good crystals have come from the Schneeberg District in the Erzgebirge, Saxony, Germany; and small interconnected crystals from Manuel-Mercedes Mine, Cala, Andalusia, Spain. In Canada, Skutterudite is found in the ore
fields at Cobalt, Timiskaming District, Ontario.
Well-formed crystals of Nickelskutterudite have come from the Schlema and Schneeberg Districts, Erzgebirge, Saxony, Germany.
Distingushing Similar Minerals
Arsenopyrite - Forms in different crystal habits, darker streak.
- Usually has a yellowish color that is lacking in Skutterudite.