Quartz (Water-worn pebble)

Physical Properties

Hardness: 7 (Mohs scale); Color: Milky white to translucent with dark mineral inclusions/staining; Luster: Vitreous to waxy; Crystal Structure: Trigonal (often appears amorphous in smooth pebbles); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Formation & Geological History

Formed from silica-rich hydrothermal fluids or within igneous and metamorphic rocks. This specific specimen has been chemically or mechanically weathered and rounded by water transport in a river or beach environment over thousands of years.

Uses & Applications

Industrial use for glass production, electronics (piezoelectric properties), abrasives, and as decorative stone or jewelry (when polished).

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. These specific rounded stones are often called 'river rocks' or 'beach pebbles' and their smooth texture is the result of natural rock tumbling by water.

Field Identification & Locations

Identify in the field by its hardness (will scratch glass and steel), lack of visible grains like sandstone, and its smooth, waxy surface when found in water beds. It is resistant to chemical weathering.

Identified on: 4/27/2026

Mode: Standard