Volcanic glass (SiO2 rich)Amorphous

Pumice

Volcanic glass (SiO2 rich)

Mineraloids
Chemical FormulaVolcanic glass (SiO2 rich)
Crystal SystemAmorphous
Mohs Hardness6
Specific Gravity0.5
ColorWhite, gray, light gray
LusterVitreous
StreakWhite
CleavageNone
FractureConchoidal

Occurrence

Lightweight volcanic rock. Floats on water. Used as abrasive.

Hardness on Mohs Scale

6 / 10
Talc (1)Quartz (7)Diamond (10)