Quartz (Milky/Common)
Silicon Dioxide (SiO2)
Rock Type: mineral

Physical Properties
Hardness: 7 (Mohs scale), Color: White to translucent gray, Luster: Vitreous to greasy, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & Geological History
Formed from cooling magma or hydrothermal veins. It is one of the most abundant minerals in the Earth's crust and can be found in rocks from nearly every geological age.
Uses & Applications
Used in glass manufacturing, electronics (due to piezoelectric properties), abrasives, construction as aggregate, and decorative jewelry/ornaments.
Geological Facts
Quartz is highly resistant to both chemical and physical weathering. It is the main component of most beach sands and is frequently the last mineral remaining after others have decomposed.
Field Identification & Locations
Identify by its ability to scratch glass and steel, lack of cleavage (it breaks like glass), and its hexagonal crystal habit if present. It is found globally in mountains, riverbeds, and beaches.
Identified on: 4/17/2026
Mode: Standard