pyrophyllite
Sign in to savePyrophyllite is a phyllosilicate mineral composed of aluminium silicate hydroxide: Al2Si4O10(OH)2. It occurs in two forms (habits): crystalline folia and compact masses; distinct crystals are not known.
Key facts
- Mineral.name
- Pyrophyllite
- Mineral.category
- Phyllosilicate minerals
- Mineral.group
- Pyrophyllite-Talc group
- Mineral.boxbgcolor
- dfce9d
- Mineral.image
- Pyrophyllite-118706.jpg
- Mineral.imagesize
- 260px
- Mineral.caption
- Pearly radial cluster of pyrophyllite from Hillsborough District, Orange County, North Carolina (Size: 11 × 7.3 × 6.6 cm)
- Mineral.formula
- Al2Si4O10(OH)2
- Mineral.IMAsymbol
- Prl
- Mineral.molweight
- 360.31 g/mol
- Mineral.system
- Monoclinic or triclinic
- Mineral.class
- Prismatic (2/m) or pinacoidal ()
- Mineral.symmetry
- C2/c or C
- Mineral.unit cell
- a = 5.16 Å, b = 8.966(3) Å, c = 9.347(6) Å; α = 91.18°, β = 100.46°, γ = 89.64°; Z = 2
- Mineral.color
- Brown green, brownish yellow, greenish, gray green, gray white
- Mineral.habit
- Compact spherulitic aggregates of needlelike radiating crystals; as fine grained foliated laminae, granular, massive
- Mineral.cleavage
- [001] Perfect
- Mineral.tenacity
- Flexible inelastic
via Wikipedia infobox
Wikidata facts
- Image
- Pyrophyllite-386094.jpg
Show 6 more facts
- Nickel-Strunz 9th edition (updated 2009)
- 9.EC.10
- Commons category
- Pyrophyllite
- Nickel-Strunz '10th ed', review of (9th ed/ 2009 update)
- 9.EC.10
- IMA Mineral Symbol
- Prl
- chemical formula
- Al₂Si₄O₁₀(OH)₂
- Strunz 8th edition (series ID, updated)
- VIII/E.04
Sources (2)
via Wikidata · CC0
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Article
5 sectionsContents
- Occurrence
- Uses
- See also
- References
- External links
Pyrophyllite is a phyllosilicate mineral composed of aluminium silicate hydroxide: Al2Si4O10(OH)2. It occurs in two forms (habits): crystalline folia and compact masses; distinct crystals are not known.
The folia have a pronounced pearly luster, owing to the presence of a perfect cleavage parallel to their surfaces: they are flexible but not elastic, and are usually arranged radially in fan-like or spherical groups. This variety, when heated, exfoliates and swells up to many times its original volume. The color of both varieties is white, pale green, greyish or yellowish; they are very soft (hardness of 1.0 to 1.5) and are greasy to the touch. The specific gravity is 2.65–2.85. The two varieties are thus very similar to talc.