Milky Quartz (with potential inclusion)

Silicon Dioxide (SiO2)

Rock Type: mineral

Milky Quartz (with potential inclusion)

Physical Properties

Hardness: 7 on Mohs scale; Color: Milky white to greyish (due to fluid/gas inclusions); Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & Geological History

Forms in a wide variety of environments, most commonly via hydrothermal veins or cooling of silica-rich magma/pegmatites. It is found in geological formations ranging from the Precambrian to recent times.

Uses & Applications

Used widely in glass making, ceramics, as an abrasive, in the semiconductor industry, and as an ornamental stone or collector specimen.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz specifically gets its opaque appearance from tiny bubbles of gas or liquid trapped during the crystal's growth.

Field Identification & Locations

Identify in the field by its hardness (will scratch glass), lack of cleavage, and characteristic waxy/vitreous luster. Common in riverbeds, mountains, and as vein material in other rocks.

Identified on: 4/22/2026

Mode: Standard