Quartz in Matrix (possibly with Biotite or Hornblende)

Physical Properties

Hardness: 7 (Quartz); Color: Clear to white translucent with black/grey host rock; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Formation & Geological History

Formed through the cooling and crystallization of silica-rich magma or from hydrothermal fluids filling veins in existing rock. This specimen appears to be 'bull quartz' or a vein fragment, typically found in igneous terranes or metamorphic belts of varying geological ages.

Uses & Applications

Used widely in glass manufacturing, electronics (due to piezoelectric properties), construction as aggregate, and as common decorative specimens for amateur collectors.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. It is extremely resistant to both chemical and physical weathering, which is why it often remains as large chunks while surrounding minerals erode away.

Field Identification & Locations

Identify in the field by its ability to scratch glass, its lack of cleavage (it breaks like glass), and its greasy/glassy luster. Frequently found in riverbeds, mountains, and near granite outcrops.

Identified on: 4/26/2026

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