Quartz

Physical Properties

Hardness: 7 on Mohs scale; Color: Often yellow-orange (iron staining) or white/clear; Luster: Vitreous (glassy); Crystal structure: Trigonal; Cleavage: None (exhibits conchoidal fracture).

Formation & Geological History

Forms in a wide variety of igneous, metamorphic, and sedimentary environments. Often crystallizes from silica-rich magma or precipitates from hydrothermal solutions.

Uses & Applications

Used extensively in electronics, glass making, construction, and sometimes as semi-precious gemstones or for lapidary work.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is known as rock crystal, while impurities produce varieties like amethyst, citrine, and rose quartz.

Field Identification & Locations

Identified by its hardness (scratches glass), lack of cleavage, and conchoidal fracture. Common worldwide. Often found in hydrothermal veins, pegmatites, and as a primary constituent of granite and sandstone.

Identified on: 4/25/2026

Mode: Advanced