mineral

Smoky Quartz and Citrine

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale), Color: Smoky grey-brown and pale yellowish-gold, Luster: Vitreous (glassy), Crystal system: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified July 7, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: Smoky grey-brown and pale yellowish-gold, Luster: Vitreous (glassy), Crystal system: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & geological history

Formed in igneous and metamorphic environments, specifically pegmatites and hydrothermal veins. These specimens are tumbled, meaning they were smoothed in a rotary machine to mimic river-worn erosion.

Uses & applications

Used primarily in jewelry, as ornamental stones, for crystal collecting, and historical use in early optical components.

Geological facts

Naturally occurring Citrine is rare; much commercial citrine is actually heat-treated Amethyst. Smoky quartz gets its color from natural irradiation of aluminum impurities within the crystal lattice.

Field identification & locations

Identify by their glassy luster and hardness (cannot be scratched by a steel knife). Common locations include Brazil, Madagascar, and the United States (Colorado).