Quartz

Physical Properties

Hardness: 7 on Mohs scale; Color: Milky white to colorless/transparent; Luster: Vitreous (glassy) to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & Geological History

Formed through the cooling of silica-rich magma or precipitation from hydrothermal veins. It is found in all types of geological environments (igneous, metamorphic, and sedimentary) across all geological ages.

Uses & Applications

Used extensively in glassmaking, electronics (oscillators), abrasives, construction (as part of granite or sand), and as gemstones/ornamental carvings.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. It is piezoelectric, meaning it generates an electric charge in response to applied mechanical stress, which is why it is used in watches and radios.

Field Identification & Locations

Identify in the field by its hardness (will scratch glass), lack of cleavage, and characteristic glassy luster. Commonly found in riverbeds, mountain outcrops, and as milky white veins in darker rocks.

Identified on: 4/16/2026

Mode: Standard