page_title: Pentlandite
hierarchical_section_title: Pentlandite
caption_attribution_description: Pentlandite in pyrrhotite from the Sudbury Impact Structure in Ontario, Canada. (field of view 3.4 cm across) Pentlandite is the principal nickel ore mineral. It is a brassy gold-colored nickel iron sulfide (Ni,Fe)9S8). It's similar in its physical properties to other brassy gold-colored sulfide minerals such as pyrite, pyrrhotite, and chalcopyrite. Pentlandite has a metallic luster, a brassy-bronze color, a light bronzish-brown streak, has a hardness of 3.5 to 4, is not magnetic, has no cleavage, and is moderately heavy for its size. Pentlandite is typically found closely intermingled with pyrrhotite (Fe1-xS), as in the examples shown below. Pentlandite crystals are rare, and it usually occurs in massive to granular form. Pentlandite can be found with other metallic sulfide minerals, particularly in some mafic and ultramafic intrusive igneous rocks. The Sudbury Impact Structure of Ontario is a world-class locality for pentlandite and other metallic sulfides. The massive sulfide rock shown above is from Sudbury. The Sudbury Complex (Sudbury Basin) in southeastern Canada has intrigued geologists for decades, and not just due to the tremendous economic value of the area’s mineral deposits. Sudbury is one of the largest preserved impact structures on Earth. The impact occurred ~1.85 billion years ago, during the late Paleoproterozoic. The Sudbury Impact Structure is no longer circular or subcircular in shape, however - it's been compessed into a stretched-egg shape from an ancient continental collision event. This massive sulfide specimen consists of bright brassy-colored patches of pentlandite ((Ni,Fe)9S8 - nickel iron sulfide) in brassy gray-brown pyrrhotite (Fe(1-x)S - imperfect iron monosulfide), plus a network of grayish to black patches of magnetite (Fe3O4 - iron oxide). Sulfide mineralization likely occurred during or very soon after the Sudbury impact event at 1.85 billion years (Paleoproterozoic). Locality: South Mine, near Sudbury, southeastern Ontario, southeastern Canada Photo gallery of pentlandite: www.mindat.org/gallery.php?min=3155
context_page_description: Pentlandite is an iron–nickel sulfide, (Fe, Ni)₉S₈. Pentlandite has a narrow variation range in Ni:Fe but it is usually described as having a Ni:Fe of 1:1. It also contains minor cobalt, usually at low levels as a fraction of weight.
  Pentlandite forms isometric crystals, but it is normally found in massive granular aggregates. It is brittle with a hardness of 3.5–4 and specific gravity of 4.6–5.0 and is non-magnetic. It has a yellowish bronze color.
  Pentlandite has been investigated as a catalyst for the hydrogen evolution reaction in water electrolysis.
context_section_description: Pentlandite is an iron–nickel sulfide, (Fe,Ni)₉S₈. Pentlandite has a narrow variation range in Ni:Fe but it is usually described as having a Ni:Fe of 1:1. It also contains minor cobalt, usually at low levels as a fraction of weight.
  Pentlandite forms isometric crystals, but it is normally found in massive granular aggregates. It is brittle with a hardness of 3.5–4 and specific gravity of 4.6–5.0 and is non-magnetic. It has a yellowish bronze color.
  Pentlandite has been investigated as a catalyst for the hydrogen evolution reaction in water electrolysis.
caption: Pentlandite in pyrrhotite, ore specimen from the Sudbury Basin (field of view 3.4 cm)
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