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pyrrhotite
Pyrrhotite (pyrrhos in Greek meaning "flame-coloured") is an iron sulfide mineral with the formula Fe(1−x)S (x = 0 to 0.125). It is an iron-deficient nonstoichiometric variant of FeS, the mineral known as troilite. Pyrrhotite is also called magnetic pyrite, because the color is similar to pyrite and it is weakly magnetic. The magnetism decreases as the iron content increases, and troilite is non-magnetic. Pyrrhotite is generally tabular and brassy/bronze in color with a metallic luster. The mineral occurs with mafic igneous rocks like norites, and may form from pyrite during metamorp
Key facts
- Mineral.name
- Pyrrhotite
- Mineral.image
- Pyrrhotite-Sphalerite-Quartz-195225.jpg
- Mineral.imagesize
- 260px
- Mineral.caption
- Brassy, tabular crystals of pyrrhotite, with sphalerite and quartz, from Nikolaevskiy Mine, Primorskiy Kray, Russia. Specimen size: 5.3 × 4.1 × 3.8 cm
- Mineral.formula
- Fe1−xS (x = 0 to 0.125)
- Mineral.IMAsymbol
- Pyh
- Mineral.strunz
- 2.CC.10
- Mineral.system
- Monoclinic, with hexagonal polytypes
- Mineral.class
- Prismatic (2/m) (same H-M symbol)
- Mineral.symmetry
- A2/a
- Mineral.unit cell
- a = 11.88 Å, b = 6.87 Å, c = 22.79 Å; β = 90.47°; Z = 26
- Mineral.color
Article
23 sectionsContents
- Structure
- Magnetic properties
- Identification
- Physical properties
- Optical properties
- Occurrence
- Formation
- Distribution
- United States
- Mining locations worldwide
- Canada
- US
- Australia
- Brazil
- Italy
- Kosovo
- Etymology and history
- Sulfide oxidation in construction aggregates leading to concrete degradation
- Uses
- Mineral abbreviations
- Synonyms
- References
- External links
Pyrrhotite (pyrrhos in Greek meaning "flame-coloured") is an iron sulfide mineral with the formula Fe(1−x)S (x = 0 to 0.125). It is an iron-deficient nonstoichiometric variant of FeS, the mineral known as troilite. Pyrrhotite is also called magnetic pyrite, because the color is similar to pyrite and it is weakly magnetic. The magnetism decreases as the iron content increases, and troilite is non-magnetic. Pyrrhotite is generally tabular and brassy/bronze in color with a metallic luster. The mineral occurs with mafic igneous rocks like norites, and may form from pyrite during metamorphic processes. Pyrrhotite is associated and mined with other sulfide minerals like pentlandite, pyrite, chalcopyrite, and magnetite, and has been found globally. thumb|Nickel arsenide#Crystal structure|NiAs structure of basic pyrrhotite-1C. thumb|Pyrrhotite with pentlandite (late Paleoproterozoic, 1.85 G… | Flickr thumb|Microscopic image of pyrrhotite under reflected light
==Structure== Pyrrhotite exists as a number of polytypes of hexagonal or monoclinic crystal symmetry; several polytypes often occur within the same specimen. Their structure is based on the NiAs unit cell. As such, Fe occupies an octahedral site and the sulfide centers occupy trigonal prismatic sites.