mineral

Quartz crystal cluster

Quartz (silicon dioxide, SiO₂)

AI-generated identification · may be incorrect

Hardness 7 Mohs; colorless to milky with a glassy luster and typically hexagonal/trigonal crystals. It has conchoidal fracture, no true cleavage, and a specific gravity near 2.65.

Identified September 6, 2026More mineral →

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Physical properties

Hardness 7 Mohs; colorless to milky with a glassy luster and typically hexagonal/trigonal crystals. It has conchoidal fracture, no true cleavage, and a specific gravity near 2.65.

Formation & geological history

Forms when silica-rich hydrothermal fluids or groundwater precipitate quartz in cavities, veins, and fractures; the specimen appears to be quartz attached to a darker matrix. Individual crystals may form over a wide range of geological ages.

Uses & applications

Used in glass, ceramics, electronics, abrasives, and engineered stone; attractive clusters are sold as décor and mineral specimens. This small, included cluster has modest jewelry value unless locality or clarity is exceptional.

Geological facts

The pointed, glassy prismatic crystals and lack of obvious cleavage distinguish quartz from calcite. Dark inclusions or matrix may be iron/manganese oxides or another host mineral.

Field identification & locations

Common worldwide, including Brazil, Arkansas, Madagascar, Switzerland, and many hydrothermal vein districts. Field tests include scratching glass, observing six-sided/prismatic crystal faces, and checking that dilute acid does not noticeably fizz.