Quartz (Common or Milky)

Physical Properties

Hardness: 7 on Mohs scale; Color: Colorless to white/translucent with brownish surface staining; Luster: Vitreous when fresh, waxy when weathered; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & Geological History

Formed during the cooling of silica-rich magma or through hydrothermal activity. Found in various geological environments including pegmatites and metamorphic veins. This specimen shows signs of mechanical weathering or transport.

Uses & Applications

Used in glass manufacturing, electronics (piezoelectric properties), abrasives, and as a raw material for silicon-based products. Also used in construction aggregate and as a low-cost gemstone or specimen for collectors.

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 persists as pebbles or grains after other minerals have eroded away.

Field Identification & Locations

Identified in the field by its hardness (it will easily scratch glass and stainless steel), lack of cleavage, and translucent appearance. It is ubiquitous in riverbeds, mountains, and beaches worldwide.

Identified on: 5/13/2026

Mode: Standard