VS
Name
—
(Y,Ca)₅(SiO₄)₃(OH)
Formula
—
Mineral Species
Entry type
—
Silicates
Chemical class
—
Monoclinic
Crystal system
—
6
Mohs hardness
—
4.35
Specific gravity
—
Faint brown
Streak
—
Resinous to dull
Luster
—
Imperfect on {0001}, {1010}
Cleavage
—
P2_1
Space group
—
Apatite
Structural group
—
Bri-Y · Approved
IMA
—
1938
Named in
—
Dark reddish brown; in thin section, yellowish brown
Typical colors
—
Y · Ca · Si · O · H
Elements
—