mineral

Polished quartz pebble with iron-oxide inclusions

Quartz, SiO₂; likely included or milky quartz

AI-generated identification · may be incorrect

Mohs hardness 7; translucent gray-white body with reddish-brown inclusions, vitreous to waxy luster, and no visible cleavage. Quartz is trigonal and has conchoidal fracture; the smooth shape is human-polished or water-worn.

Identified August 21, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids, igneous melts, or sedimentary veins; iron oxides later stain or line fractures. Quartz occurs from Precambrian formations to the present, so age cannot be determined visually.

Uses & applications

Used as a decorative tumbled stone, cabochon, and collector specimen; quartz is also important in glass, electronics, abrasives, and construction aggregate.

Geological facts

The reddish material is probably hematite or goethite, while cloudy areas reflect microscopic fluid inclusions or fractures. Quartz is one of Earth’s most abundant minerals.

Field identification & locations

Identify it by its glassy appearance, hardness sufficient to scratch ordinary glass, and lack of cleavage; iron staining produces red-brown patches. Common worldwide, especially in hydrothermal veins and quartz-rich gravels.