Sliced onyx geode

General

 

Category: Oxide mineral

 

Formula: Silica (silicon dioxide, SiO2)

 

Crystal system: Trigonal

 

 

Identification

 

Formula mass: 60 g/mol

 

Color: Various

 

Cleavage: no cleavage

 

Fracture: Uneven, conchoidal

 

Mohs scale hardness: 6.5–7

 

Luster: Vitreous, silky

 

Streak: White

 

Diaphaneity: Translucent

 

Specific gravity: 2.55–2.70

 

Optical properties: Uniaxial/+

 

Refractive index: 1.530 to 1.543

Done