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.
Chloanthite 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.