Quartz (Milky Quartz)

Physical Properties

Hardness: 7 on Mohs scale; Color: Opaque white with reddish-brown iron staining; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Formation & Geological History

Formed from the cooling of silica-rich hydrothermal solutions or within igneous pegmatites. It is one of the most abundant minerals in Earth's crust and can be found in rocks of all geological ages.

Uses & Applications

Used in glassmaking, abrasives, electronics (piezoelectric properties), and as a common landscaping or decorative stone. High-purity quartz is essential for silicon wafer production.

Geological Facts

Milky quartz gets its white, opaque appearance from tiny fluid inclusions of gas and/or liquid trapped during crystal growth. It is the most common variety of crystalline quartz.

Field Identification & Locations

Identify in the field by its ability to scratch glass, its lack of cleavage, and its characteristic 'greasy' luster on fractured surfaces. It is found globally in mountains, riverbeds, and beaches.

Identified on: 4/16/2026

Mode: Standard