VS
Name
—
(Ta₀.₆ ₀.₄)Al₆BSi₃O₁₈
Formula
—
Mineral Species
Entry type
—
Silicates
Chemical class
—
Orthorhombic
Crystal system
—
8.5
Mohs hardness
—
3.6–3.9
Specific gravity
—
Light buff
Streak
—
Resinous, vitreous, dull when weathered
Luster
—
Good on {001}, may be parting
Cleavage
—
Pnma
Space group
—
Dumortierite
Structural group
—
Hlt · Approved
IMA
—
1969
Named in
—
Light buff to cream-buff or deep olive-buff, brown, russet
Typical colors
—
Ta · Al · B · Si · O
Elements
—