About Pyrrhotite
Fe₁₋ₓS (x = 0-0.17)
Bronze-coloured, magnetic iron sulfide with a variable iron deficit, typically platy pseudohexagonal crystals or massive ore; it tarnishes quickly.
Photos of Pyrrhotite
Sharp single bladed pyrrhotite crystal on black sphalerite and quartz, Dalnegorsk.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Hexagonal 'poker chip' pyrrhotite crystal among smaller crystals and massive sulfides, Santa Eulalia.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Cluster of intergrown, tarnished pseudohexagonal pyrrhotite crystals from the Nikolaevskiy Mine.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Pyrrhotite-sphalerite skarn ore from the Ward Mine, Nevada (view 1).
Photo: James St. John · CC BY 2.0 · Source
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Brassy compound pyrrhotite crystal with natural etching from the Trepca complex.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Two intergrown bronzy pyrrhotite crystals with accent calcite from the Morro Velho Mine.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Massive pyrrhotite with pentlandite, chalcopyrite and magnetite from Worthington, Sudbury.
Photo: James St. John · CC BY 2.0 · Source
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Massive pyrrhotite with pentlandite and chalcopyrite from the Gap Nickel Mine, Pennsylvania.
Photo: James St. John · CC BY 2.0 · Source
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Where Pyrrhotite is found (9)
Brazil
- Morro Velho MineMinas Gerais · 2 photos
Canada
- Bluebell Mine (Riondel)British Columbia · 1 photo
- Worthington MineOntario · 2 photos
Kosovo
- Trepca complexMitrovica District · 3 photos
Mexico
- Santa Eulalia Mining DistrictChihuahua · 5 photos
Russia
- DalnegorskPrimorsky Krai · 5 photos
- Nikolaevskiy MinePrimorsky Krai · 5 photos
United States
- Gap Nickel Mine (Nickel Mines)Pennsylvania · 1 photo
- Ward MineNevada · 3 photos
Pyrrhotite on the same specimen with other minerals
2 specimen photo(s) from this locality show marcasite with pyrrhotite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
1 specimen photo(s) from this locality show galena with pyrrhotite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
1 specimen photo(s) from this locality show dolomite with pyrrhotite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
1 specimen photo(s) from this locality show siderite with pyrrhotite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
1 specimen photo(s) from this locality show siderite with pyrrhotite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
1 specimen photo(s) from this locality show pyrrhotite with galena together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
2 specimen photo(s) from this locality show pyrrhotite with quartz together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
1 specimen photo(s) from this locality show pyrrhotite with siderite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
1 specimen photo(s) from this locality show pyrrhotite with galena together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
1 specimen photo(s) from this locality show pyrrhotite with galena together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
2 specimen photo(s) from this locality show pyrrhotite with quartz together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
1 specimen photo(s) from this locality show pyrrhotite with quartz together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
1 specimen photo(s) from this locality show pyrrhotite with sphalerite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
1 specimen photo(s) from this locality show pyrrhotite with galena together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.
Identity
- Also called
- magnetic pyrites
- Strunz
- 2.CC.10 · 2 Sulfides and sulfosalts
- Name origin
- From Greek for 'redness', in allusion to its colour.
- Elements
- Fe, S
Physical properties
- Color
- Bronze-yellow to pinchbeck-brown; tarnishes quickly, rarely iridescent
- Streak
- Dark grayish black
- Luster
- Metallic luster
- Transparency
- Opaque
- Mohs hardness
- 3.5–4.5
- Density
- 4.58–4.65 g/cm³
- Cleavage / fracture
- No true cleavage; distinct parting on {0001}; fracture uneven to subconchoidal
- Magnetism / fluorescence
- Magnetic; strength varies inversely with iron content
Crystallography
- Crystal system
- Monoclinic
- Space group
- A2/a
- Structure
- Pseudohexagonal, iron-deficient iron monosulfide with many polytypes (4M, 6M, 5H, 7H, 11H); a high-temperature hexagonal form may persist at room temperature.
- Typical habit
- Tabular to platy crystals on {0001}, steep or short pyramidal crystals, rosettes of nearly parallel plates; commonly massive or granular
- Twinning
- On {10-12}
- Optical data
- Opaque; in reflected light weak pleochroism and strong anisotropism; reflectance about 28-44 % across the visible range
Formation and use
- Formation
- Mainly in mafic igneous rocks as magmatic segregations; also in pegmatites, high-temperature hydrothermal and replacement veins and skarns, and in sedimentary and metamorphic rocks; in iron meteorites.
- Uses
- Major component of magmatic nickel-copper sulfide ores (with pentlandite and chalcopyrite), e.g. at Sudbury; collector specimens.
- Stability and care
- Tarnishes quickly in air.
Related minerals
- Related minerals
- Troilitesmythite
Sources
- SRC-627 · Book
Handbook of Mineralogy - PyrrhotiteAnthony, J.W.; Bideaux, R.A.; Bladh, K.W.; Nichols, M.C. · 2005 · Mineral Data Publishing / Mineralogical Society of America - SRC-628 · Database
Pyrrhotite Mineral DataBarthelmy, D. · Webmineral.com - SRC-630 · Database
Worthington Mine (MDI41I06NW00005), Ontario Mineral InventoryOntario Geological Survey · Ontario Ministry of Mines - GeologyOntario
Draft data from the Provenite workbook. Check entries against the cited sources before relying on them. Photos are open-licence images from Wikimedia Commons; the author and licence are given with each photo.