Lithium Mica
K(Li,Al)3(Al,Si,Rb)4O10 (F,OH)2
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Chemical name
Lithium Mica |
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Mineral name
Lepidolite |
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Chemical formula
K(Li,Al)3(Al,Si,Rb)4O10
(F,OH)2 |
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Crystal system
monoclinic |
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Crystal Class
monoclinic-prismatic (2/m) |
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Space Group
C2/m |
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Unit cell
a [Å]:5.21 b [Å]:8.97 c [Å]:20.16 |
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Molecular weight [g/mol]
388.30 |
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Formula units
Z=2 |
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Twinning
rare, composition plane on {001} |
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Mohs hardness
2.5 - 3 |
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Density [g/cm3]
2.8 - 2.9 |
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Cleavage
perfect on {001} |
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Fracture / Tenacity
uneven |
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Color
pink, purple, rose-red, violet-gray, yellowish, white, colorless |
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Streak
white |
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Transparency
transparent to translucent |
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Luster
vitreous to pearly |
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Optical character
biaxial (-) |
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Refractive Index
nα=1.525-1.548; nβ=1.551-1.580; nΥ=1.554-1.586 |
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Birefringence δ
0.029 - 0.038 |
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Pleochroism δ
moderate to strong |
