grunerite
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Grunerite is a mineral of the amphibole group of minerals with formula Fe7Si8O22(OH)2. It is the iron endmember of the grunerite-cummingtonite series. It forms as fibrous, columnar or massive aggregates of crystals. The crystals are monoclinic prismatic. The luster is glassy to pearly with colors ranging from green, brown to dark grey. The Mohs hardness is 5 to 6 and the specific gravity is 3.4 to 3.5.
Key facts
- Mineral.name
- Grunerite
- Mineral.image
- Grunerite-648168.jpg
- Mineral.caption
- Sprays of small, prismatic grunerite crystals on matrix, field of view 5mm, from Marquette Co., Michigan, US
- Mineral.category
- Inosilicate
- Mineral.formula
- Fe7Si8O22(OH)2
- Mineral.IMAsymbol
- Gru
- Mineral.molweight
- 1,001.61 g/mol
- Mineral.strunz
- 9.DE.05
- Mineral.system
- Monoclinic
- Mineral.class
- Prismatic (2/m) (same H-M symbol)
- Mineral.symmetry
- C2/m
- Mineral.color
- Ashen, brown, brownish green, dark gray
- Mineral.habit
- Columnar, acicular
- Mineral.mohs
- 5–6
- Mineral.luster
- Vitreous
- Mineral.streak
- Colorless
- Mineral.diaphaneity
- Translucent to opaque
- Mineral.gravity
- 3.45
via Wikipedia infobox
Wikidata facts
- Image
- Gruenerite Schist Metamorphic Rock North of Keystone, South Dakota 2916.jpg
Show 6 more facts
- Nickel-Strunz 9th edition (updated 2009)
- 9.DE.05
- Nickel-Strunz '10th ed', review of (9th ed/ 2009 update)
- 9.DE.05
- Commons category
- Grunerite
- IMA Mineral Symbol
- Gru
- chemical formula
- ☐Fe²⁺₂Fe²⁺₅Si₈O₂₂(OH)₂
- Strunz 8th edition (series ID, updated)
- VIII/D.05a
via Wikidata · CC0
~1 min read
Article
3 sectionsContents
- Amosite (fibrous grunerite)
- References
- External links
Grunerite is a mineral of the amphibole group of minerals with formula Fe7Si8O22(OH)2. It is the iron endmember of the grunerite-cummingtonite series. It forms as fibrous, columnar or massive aggregates of crystals. The crystals are monoclinic prismatic. The luster is glassy to pearly with colors ranging from green, brown to dark grey. The Mohs hardness is 5 to 6 and the specific gravity is 3.4 to 3.5.
It was discovered in 1853 and named after Emmanuel-Louis Gruner (1809–1883), the Swiss-French chemist who first analysed it.