SiO2Trigonal
Chalcedony
SiO2
SilicatesChemical FormulaSiO2
Crystal SystemTrigonal
Mohs Hardness7
Specific Gravity2.6
ColorWhite, gray, blue, pink
LusterVaxy to vitreous
StreakWhite
CleavageNone
FractureConchoidal
Occurrence
Microcrystalline quartz. Includes agate, onyx, jasper, carnelian as varieties.