mineral

Smoky quartz crystal on a pale quartz matrix

Quartz, SiO₂; smoky variety colored by irradiation-related defects

AI-generated identification · may be incorrect

The dark, glassy prismatic crystal appears to be smoky quartz, attached to colorless or milky quartz. Quartz has Mohs hardness 7, a trigonal crystal structure, vitreous luster, and no cleavage; the photo does not permit reliable measurement of specific gravity.

Identified October 16, 2026More mineral →

Explore Smoky quartz crystal on a pale quartz matrix in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Quartz typically crystallizes from silica-rich fluids in fractures, veins, or cavities, commonly in granitic pegmatites and hydrothermal settings. Its age depends on the host deposit and cannot be determined from the image.

Uses & applications

Quartz specimens are collected and displayed; clear quartz is also used in jewelry, glassmaking, and electronics. This piece appears primarily suited to collecting.

Geological facts

Smoky quartz gets its brown-to-black color from irradiation acting on trace aluminum-related defects in the crystal lattice.

Field identification & locations

Look for a glassy luster, six-sided prismatic crystal faces, and hardness sufficient to scratch glass; smoky color distinguishes it from clear quartz. Quartz occurs worldwide, especially in granites, pegmatites, and hydrothermal veins.