Pentlandite

Pentlandite Group. Cobaltpentlandite-Pentlandite Series. Pentlandite is a rather pale brassy yellow metallic sulphide, one of the most important nickel ores, and a primary mineral in many ultramafic rocks. It is usually found associated, and commonly finely intergrown, with pyrrhotite, and rarely shows microscopically visible crystals. It is difficult to confirm visually but sometimes can be distinguished by its paler colour, octahedral cleavage, and non-magnetic nature. Compare also the chemically similar mackinawite, godlevskite and horomanite; 'UM1981-13-S:CoFeNiRh' and 'UM1989-25-S:FeNi'.

History

Activities related to discovery and approval of the group members

Structural context

Pentlandite
Crystal System isometricCrystal Class hexoctahedralSpace Group Fm-3m
a9.91—10.2349 (10.0754)
b9.91—10.2349 (10.0754)
c9.91—10.2349 (10.0754)
alpha90
beta90
gamma90
volume973.2—1072.14 (1022.895)

Based on 51 measurements

Chemical context

Stoichiometric formulas

Pentlandite
mindat.org
  • March 13, 2023(NixFey)Σ9S8x+y=9. IMA formula is: (Ni,Fe)9S8. Most samples are Ni-dominant, but some are Fe-dominant. Typical analyses: (Ni4.60Fe4.30Co0.17)Σ=9.07S8.00 (Ni4.16Fe3.63Co1.48)Σ=9.27S8.00 (Ni5.89Fe2.51Co0.53)Σ=8.93S8.00 (Fe4.80Ni4.12Co0.08)Σ=9S8
IMA
  • March 13, 2023(Ni,Fe)9S8
mineralogy.rocks
  • Aug. 30, 2022(Ni,Fe)9S8

Elements recorded on EPMA

51
Fe
51
Ni
51
S
11
Co

Physical properties

ColorColor entities, recognized using a custom trained NER model
  • pale bronze-yellow
  • bronze
  • reddish brown
Color noteOriginal color note from the source
Pale bronze-yellow; bronze; brown; reddish brown when argentian
StreakStreak entities, recognized using a custom trained NER model
  • pale bronze-brown
Streak noteOriginal streak note from the source
Pale bronze-brown
Lustre
Metallic
Fracture
Conchoidal
Transparency
Opaque
Luminescence
None
Tenacity
brittle
Hardness
3.5—4
Measured density
4.6—5
Calculated density
4.956