Chert
Chemical Formula	SiO2
Species	Silicates
Crystal System	Trigonal
Mohs Scale	6-7
Specific Gravity	2.59-2.63
Color	Gray, white; black, brown and other colors due to staining
Streak	White or lightly colored
Luster	Waxy, Dull
Diaphaneity	Translucent, Opaque
Cleavage	None Observed
Fracture	Splintery, Conchoidal, Sub-Conchoidal