mineral

Quartz (Smoky/Milky)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale. Color: Translucent grey to white. Luster: Vitreous (glassy). Crystal Structure: Hexagonal/Trigonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Translucent grey to white
Luster: Vitreous (glassy)

Identified June 15, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale. Color: Translucent grey to white. Luster: Vitreous (glassy). Crystal Structure: Hexagonal/Trigonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Formation & geological history

Formed through the crystallization of magma or from hydrothermal veins. Smoky varieties often get their color from natural irradiation of aluminum impurities over millions of years.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as semi-precious gemstones in jewelry or decorative carvings.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Smoky quartz is the national gem of Scotland, where it is often called Cairngorm.

Field identification & locations

Identify by its hardness (will scratch glass) and lack of cleavage. Look for it in granitic rocks, pegmatites, and riverbeds globally. It is one of the most common minerals for beginning collectors.