VS
Name
—
K(Mg,Fe)₃(AlSi₃O₁₀)(OH)₂
Formula
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Mineral Group
Entry type
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Silicates
Chemical class
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Monoclinic
Crystal system
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2.5–3
Mohs hardness
—
2.8–3.4
Specific gravity
—
White to gray
Streak
—
Vitreous, Pearly to submetallic on cleavage
Luster
—
Perfect basal {001} — peels into thin elastic sheets
Cleavage
—
C2/m (1M polytype; 2M₁ and 3T also common)
Space group
—
—
Structural group
—
—
IMA
—
—
Named in
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Brown, Black
Typical colors
—
—
Elements
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