SiO2Trigonal
Carnelian
SiO2
SilicatesChemical FormulaSiO2
Crystal SystemTrigonal
Mohs Hardness7
Specific Gravity2.6
ColorOrange to red
LusterVitreous to waxy
StreakWhite
CleavageNone
FractureConchoidal
Occurrence
Red-orange variety of chalcedony. Used in jewelry since ancient times.