mineral

Tumbled and polished quartz crystal points

Quartz (silicon dioxide, SiO₂), chiefly rock crystal with smoky or included varieties

AI-generated identification · may be incorrect

Mohs hardness 7; vitreous luster; commonly colorless, gray, smoky, or dark from inclusions; trigonal crystal structure and conchoidal fracture, with no cleavage. The pieces appear cut, shaped, and polished into miniature points.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids, pegmatites, and cavities in igneous and metamorphic rocks; specimens may range from Precambrian to recent deposits. Their present shapes are human-processed rather than natural crystal terminations.

Uses & applications

Used as decorative specimens, jewelry components, metaphysical items, and ornamental displays; quartz is also important industrially in glass, ceramics, electronics, and engineered stone.

Geological facts

Quartz is one of Earth’s most abundant minerals and is piezoelectric, producing an electrical charge under pressure. Dark coloration can result from irradiation-related defects or mineral inclusions.

Field identification & locations

Identify by glassy luster, hardness sufficient to scratch ordinary glass, lack of cleavage, and conchoidal fracture; common sources include Brazil, Madagascar, China, and the United States. The pictured uniform points are likely commercially shaped quartz pieces.