mineral

Raw quartz crystal (likely smoky or iron-stained quartz)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness 7; translucent gray-brown to yellow-brown, with a vitreous luster and conchoidal fracture. Hexagonal crystal structure; cleavage is absent or very poor, and specific gravity is about 2.65.

Identified August 15, 2026More mineral →

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Physical properties

Hardness 7; translucent gray-brown to yellow-brown, with a vitreous luster and conchoidal fracture. Hexagonal crystal structure; cleavage is absent or very poor, and specific gravity is about 2.65.

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids, pegmatites, and cavities in igneous or metamorphic rocks; iron staining likely produces the brown coloration. Its exact geological age cannot be determined from the photograph.

Uses & applications

Used in glass, electronics, abrasives, and engineered stone; attractive transparent pieces may be cut as gemstones. This small rough specimen is primarily a collector sample.

Geological facts

Quartz is one of Earth’s most abundant minerals and is piezoelectric, generating an electrical charge when stressed. The apparent smoky color may result from radiation-induced defects or surface iron staining.

Field identification & locations

Identify by its glassy luster, hardness that can scratch ordinary glass, lack of cleavage, and typically irregular fracture; confirm with a hardness and streak test. Common worldwide, especially in Brazil, Madagascar, the Alps, and U.S. pegmatites.