Quartz / Quartzite

Physical Properties

Hardness: 7 on Mohs scale; Color: Milky white to translucent (sometimes stained tan/orange by iron); Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Formation & Geological History

Formed through the crystallization of silica-rich magma or precipitation from hydrothermal veins. In metamorphic form (quartzite), it results from the metamorphism of quartz-rich sandstone under heat and pressure.

Uses & Applications

Used in glass manufacturing, electronics (piezoelectric properties), abrasives, construction aggregate, and as semi-precious gemstones/jewelry.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. It is highly resistant to chemical and physical weathering, which is why it often remains as large nodules in gravel or soil.

Field Identification & Locations

Identify in the field by its hardness (will scratch glass and steel), lack of cleavage, and glassy appearance. Commonly found in riverbeds, mountains, and as veins in igneous rock.

Identified on: 4/14/2026

Mode: Standard