mineral

Quartz crystal cluster (likely smoky quartz)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent gray-brown to smoky coloration, vitreous luster, and six-sided prismatic crystals with pyramidal terminations. Quartz lacks cleavage and has conchoidal fracture; specific gravity is about 2.65.

Identified September 7, 2026More mineral →

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Physical properties

Formation & geological history

Crystallized from silica-rich hydrothermal fluids or pegmatitic cavities, probably in a granitic or metamorphic host rock. The specimen’s precise age and locality cannot be determined from the image alone; quartz deposits range from Precambrian to recent.

Uses & applications

Used for glass, electronics, abrasives, and construction aggregate; attractive clusters are collected and occasionally sold as display specimens or lapidary material.

Geological facts

The smoky color commonly results from radiation-induced color centers associated with trace aluminum. The dark matrix and drusy-to-blocky crystals suggest a cavity-filling vein or vug.

Field identification & locations

Identify by its glassy luster, hexagonal crystal forms, lack of cleavage, and ability to scratch ordinary glass. Common sources include Brazil, Madagascar, Switzerland, the United States, and China.