VS
Name
—
(Ba,Pb,K)₄(Ca,Y)₂(B,Be)₂(Si,B)₂Si₈O₂₈F
Formula
—
Mineral Species
Entry type
—
Silicates
Chemical class
—
Triclinic
Crystal system
—
5–5.5
Mohs hardness
—
3.81–3.82
Specific gravity
—
—
Streak
—
Vitreous to greasy
Luster
—
Easy in two directions at ~90°; indistinct in a third direction in the same zone as the other two
Cleavage
—
I-1
Space group
—
Hyalotekite
Structural group
—
Hya · Grandfathered
IMA
—
1877
Named in
—
White to pearly gray
Typical colors
—
Ba · Pb · K · Ca · Y · B · Be · Si · O · F
Elements
—