mineral

Quartz (Milky/Smoky variety)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale. Color: Translucent to opaque white, tan, and gray. Luster: Vitreous to greasy. Crystal structure: Hexagonal/Trigonal. Cleavage: Indistinct (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Translucent to opaque white, tan, and gray
Luster: Vitreous to greasy

Identified July 13, 2026More mineral →

Explore Quartz (Milky/Smoky variety) 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

Forms in a wide range of environments, primarily through the cooling and crystallization of silica-rich magma or from hydrothermal veins. It is found in igneous, metamorphic, and sedimentary rocks.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, construction aggregates, and as a semi-precious gemstone in jewelry and carving.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is highly resistant to chemical and physical weathering, which is why it often makes up the majority of river and beach sand.

Field identification & locations

Identify in the field by its hardness (it can scratch glass), lack of cleavage, and glassy appearance. It is found globally across all continents in mountainous and rocky terrain.