Beryl

Physical Properties
Chemical formula Be3Al2Si6O18
Class Cyclosilicate
Rings of linked tetrahedra
Crystal system Hexagonal
Habit Hexagonal prisms
Color Colorless
Blue
Red
Green (emerald)
Pale greenish blue (aquamarine)
Rose (morganite)
Gold (heliodor)
Hardness 7.5 to 8
Specific gravity 2.7 to 2.9
Cleavage Poor (001)
Fracture Even
Luster Vitreous to resinous
Transparency Transparent to translucent
Streak White
Optical Properties
PPL Colorless
Non-pleochroic
XPL 1st order grey
δ 0.006
after Perkins, 315-316

Beryl in Hand Sample

Beryl

Beryl in Thin Section

Thin Section GigaPans

Beryl in plane polars

Beryl in crossed polars

Further Reading

Beryl at webmineral.com

Beryl at mindat.org