mineral

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale. Color: White to translucent/clear. Luster: Vitreous (glassy) to greasy. Crystal structure: Trigonal/Hexagonal. Cleavage: None (conchoidal fracture). Specific gravity: 2.65.

Hardness: 7 on the Mohs scale
Color: White to translucent/clear
Luster: Vitreous (glassy) to greasy

Identified March 24, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. This specimen likely originated as a hydrothermal vein deposit that was later eroded and smoothed by water transport (river or glacial action). Quartz can be found in rocks from nearly all geological ages.

Uses & applications

Industrial uses include glassmaking, abrasives, and electronics (due to piezoelectric properties). In jewelry, it is used for beads and cabochons. Large quantities are used in construction as aggregate.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz gets its white color from tiny bubbles of gas or liquid trapped during the crystal's growth. It is highly resistant to chemical and physical weathering.

Field identification & locations

Identify in the field by its ability to scratch glass and steel, its lack of cleavage, and its waxy/glassy appearance. This rounded specimen is a common 'river rock' found in gravel pits, stream beds, and beach deposits globally.