Quartz / Milky Quartz

Physical Properties

Hardness: 7 on Mohs scale; Color: Cloudy white to grayish; Luster: Vitreous (glassy) to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & Geological History

Formed from silica-rich hydrothermal fluids or within igneous pegmatites. It is one of the most common minerals in the Earth's crust, found in virtually all geological environments from Precambrian to modern times.

Uses & Applications

Used in glassmaking, abrasives, jewelry (as semi-precious stones), and electronics due to its piezoelectric properties. Large specimens are often used for interior decor or landscaping.

Geological Facts

Quartz is known for its ability to produce an electric signal under pressure (piezoelectricity), which is why it is used in watches and computers. Milky quartz gets its cloudiness from tiny trapped bubbles of gas or liquid from its formation.

Field Identification & Locations

Identify in the field by its hardness (it will scratch glass), its lack of cleavage, and its waxy or glassy luster. It is common worldwide, especially in mountain ranges and riverbeds.

Identified on: 4/19/2026

Mode: Standard