mineral

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

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

Identified April 17, 2026More mineral →

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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.