Milky Quartz

Physical Properties

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

Formation & Geological History

Formed from hydrothermal veins or as a late-stage crystallization in igneous rocks like granite. The 'milky' appearance is caused by tiny fluid or gas inclusions trapped during crystal growth. Can be found in bedrock of almost any age.

Uses & Applications

Used in glassmaking, abrasive manufacturing, and as a source of silicon for electronics. Lower grade milky quartz is used for landscaping, construction aggregate, and occasionally tumbled for jewelry or aquarium decor.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz is the most common variety of quartz found worldwide. The white color is due to microscopic bubbles of liquid or gas trapped within the crystal structure.

Field Identification & Locations

Identify by its ability to scratch glass (hardness 7), lack of cleavage, and waxy/vitreous luster. Commonly found in riverbeds, mountains, and garden soil. It is a key indicator mineral for gold in certain hydrothermal veins.

Identified on: 4/20/2026

Mode: Standard