Chalcedony (Micro/Cryptocrystalline Quartz)SiO2|
Lustre: Vitreous / almost waxy
Habit: Aggregate of very tiny SiO2 grains.
Colours: White/gray or any colour
| ||Crystal System: Hexagonal|
Reaction with HCl: None
Identification in hand sample:
Identified by hardness and texture/habit.
Abundant in felsic rocks.
Industrial / ecomonic uses:
Used for making glass and as a source of Silicon.