Pentlandite, Chalcopyrite, and Pyrrhotite
SULFIDES; SIMPLE SULFIDES · ISOMETRIC

Pentlandite

(Fe,Ni)9S8

Hardness
3.5–4
Streak
Bronze to light brown
Spec. Gravity
4.6–5.1
System
Isometric

About

Pentlandite is an important mineral due to its nickel content, but it rarely forms in interesting specimens for collectors. It usually occurs together with Pyrrhotite, and may even be intergrown together with it.
Pentlandite is both an individual mineral, and the name of a mineral group. The Pentlandite group is composed of rare sulfides that have similar chemical structures, with Pentlandite being the most prominent member of the group. Pentlandite is named in honor of Joseph Barclay Pentland (1797–1873), a natural scientist from Ireland who first identified this mineral.

Crystal Forms & Aggregates

Striking Features

Color, mode of occurrence, and lack of magnetic properties.

Environment

Ultramafic nickel-rich ore deposits.

Uses

Pentlandite is an important ore of nickel.

Noteworthy Localities

Pentlandite is not a common mineral in collections, and few localities have produced specimens of note. The premier locality for this mineral is the Sudbury district in Ontario, Canada, especially at the Frood and Worthington Mines. Other localities include the Copper King Mine, Gold Hill, Boulder Co., Colorado; and the Bushveld Complex in Limpopo Province, South Africa. Cobalt-rich Pentlandite, known as Cobaltpentlandite, is described from the Varislahti Deposit, Karelia, Finland.

Common Mineral Associations

Distinguishing Similar Minerals

Photos