mineral

Milk Quartz (with Iron staining)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white with orange-red iron oxide streaks; Luster: Vitreous to greasy; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Milky white with orange-red iron oxide streaks
Luster: Vitreous to greasy

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed from the cooling of silica-rich hydrothermal fluids or magma. The milky appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth. Iron staining often occurs later through weathering and groundwater contact.

Uses & applications

Commonly used in industrial glass making, as an abrasive, and in construction as an aggregate. In jewelry, it is used for beads and cabochons. It is a staple for beginner rock collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is perfectly clear; the 'milkiness' of this specimen indicates it formed in a high-pressure environment where fluids were saturated.

Field identification & locations

Identify in the field by its ability to scratch glass and its lack of cleavage (it breaks in curved, shell-like patterns). It is ubiquitous worldwide, especially in mountainous regions and riverbeds.

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