Actinolite
Mineral / From Wikipedia, the free encyclopedia
This article is about the mineral. For the community in Canada, see Actinolite, Ontario.
"Uralite" redirects here. For the rail stop, see Uralite Halt railway station.
Actinolite is an amphibole silicate mineral with the chemical formula Ca2(Mg4.5–2.5Fe2+0.5–2.5)Si8O22(OH)2.
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Actinolite | |
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General | |
Category | Inosilicates |
Formula (repeating unit) | Ca2(Mg4.5-2.5Fe2+0.5-2.5) Si8O22(OH)2 |
IMA symbol | Act[1] |
Strunz classification | 9.DE.10 |
Crystal system | Monoclinic |
Crystal class | Prismatic (2/m) (same H-M symbol) |
Space group | C2/m |
Identification | |
Color | pale to dark green, yellowish green, blue and black. White or grey when in asbestos |
Crystal habit | bladed, fibrous, radial |
Twinning | simple or lamellar |
Cleavage | perfect along {110}. |
Fracture | uneven |
Mohs scale hardness | 5–6 |
Luster | vitreous to dull |
Streak | white |
Diaphaneity | translucent to transparent |
Specific gravity | 3.00 (+0.10, -0.05) |
Polish luster | vitreous |
Optical properties | Biaxial (−) |
Refractive index | nα = 1.613–1.628 nβ = 1.627–1.644 nγ = 1.638–1.655 |
Birefringence | 0.0250–0.0270 |
Pleochroism | moderate, yellow to dark green (in stones that are transparent) |
2V angle | 78–82° (calc), 84–73° (meas) |
Dispersion | r < v |
Ultraviolet fluorescence | inert |
Absorption spectra | faint line at 503 nm |
References | [2][3][4][5][6] |
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