mineral

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

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

Hardness: 7 on Mohs scale
Color: White/off-white with orange-brown iron staining
Luster: Vitreous to greasy when wet

Identified May 19, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal solutions cooling in veins or as a major constituent of igneous rocks like granite. The orange coloring is caused by surface oxidation of iron-bearing minerals during weathering.

Uses & applications

Used in glassmaking, electronics, silicon chips, and as an abrasive. Large specimens are often kept by mineral collectors or used as decorative landscaping stones.

Geological facts

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

Field identification & locations

Identify by its hardness (it will scratch glass), lack of cleavage, and waxy luster. Commonly found in riverbeds, mountain ranges, and gravel pits worldwide.

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