mineral

Quartz-rich rock, likely smoky quartz with feldspar

Quartz (SiO₂), possibly in a granitic or pegmatitic matrix

AI-generated identification · may be incorrect

Translucent gray-brown body with a vitreous luster and irregular fracture; quartz hardness is 7 Mohs, with feldspar inclusions or attached grains around 6–6.5. Crystal form is not clearly visible, so a precise identification from the photo is limited.

Identified August 25, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed in an igneous granite or pegmatite environment as silica-rich fluids cooled, probably during a Precambrian to younger geological episode depending on locality. The brown coloration may reflect natural irradiation or iron-related defects in quartz.

Uses & applications

Common quartz is used in glass, ceramics, abrasives, electronics, and decorative objects; attractive crystals are collected or used as lapidary material. This specimen appears primarily of collector interest.

Geological facts

Smoky quartz can range from pale gray to nearly black and may fade with heat or prolonged sunlight. The attached pale grains are consistent with feldspar, although visual confirmation would require testing.

Field identification & locations

Check for glassy luster, conchoidal fracture, lack of cleavage, and ability to scratch ordinary glass; feldspar inclusions commonly show cleavage. Common sources include Brazil, the United States, Switzerland, and Madagascar.