Pentlandite
Pentlandite is an iron-nickel sulfide found in carbonaceous chondrites and some ordinary chondrites.
Pentlandite is a sulfide containing both iron and nickel, with a formula close to (Fe,Ni)9S8. On Earth it is the main ore of nickel, mined from ancient magmatic deposits.
In meteorites, pentlandite is most common in carbonaceous chondrites such as the CM, CI, CR and CK groups, often intergrown with pyrrhotite. Its texture helps scientists read the history of these water-rich rocks: some grains crystallised from sulfide melts in chondrules, while others formed or changed as fluids moved through the parent asteroid. Pentlandite also appears in some ordinary chondrites and in returned samples from the asteroid Ryugu.
Under reflected light on a polished section, pentlandite is creamy and slightly brighter than pyrrhotite and is not magnetic. Its composition and the way it shares nickel with neighbouring minerals can act as a rough guide to the temperatures the rock reached.
Related terms
Level: Expert Advanced