mineral

Quartz-rich rock fragment, possibly chert or weathered quartz

Microcrystalline quartz (SiO₂), tentative identification

AI-generated identification · may be incorrect

Hardness about 7 Mohs; pale tan to gray-brown, translucent at thin edges, with a dull to waxy luster and irregular fracture. The surface appears weathered and may contain iron-oxide staining or minor matrix minerals; crystal structure is trigonal but crystals are not visibly developed.

Identified August 17, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed by silica precipitation or replacement in sedimentary rock, though the small fragment prevents confident classification; its age cannot be determined visually. Common geological settings include chert beds, quartz veins, and weathered siliceous rocks.

Uses & applications

Common chert is used historically for tools and occasionally as aggregate; quartz specimens are collected, and high-quality transparent quartz is used in jewelry and industry. This small, rough fragment has minimal commercial value.

Geological facts

Quartz is one of Earth’s most abundant minerals and commonly survives weathering because of its high hardness and chemical resistance.

Field identification & locations

Test with a steel knife or glass: genuine quartz should scratch glass and resist a knife. Common sources include sedimentary chert formations and hydrothermal quartz veins; a streak, acid test, and fresh broken surface would improve identification.