mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Opaque white; Luster: Vitreous to waxy (when polished); Crystal Structure: Hexagonal (Trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Opaque white
Luster: Vitreous to waxy (when polished)

Identified June 15, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Opaque white; Luster: Vitreous to waxy (when polished); Crystal Structure: Hexagonal (Trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Formation & geological history

Formed from hydrothermal solutions or cooling magma where gas bubbles or inclusions of fluids remain trapped during crystallization, causing the white opacity. This specimen is water-worn into a river pebble shape.

Uses & applications

Common quartz is used for abrasive sand, glassmaking, electronics (piezoelectric properties), and as decorative gravel or landscape stone.

Geological facts

Milky quartz is the most common variety of crystalline quartz. Its white color is caused by tiny fluid inclusions of gas and/or liquid trapped during crystal growth.

Field identification & locations

Identify in the field by its hardness (will scratch glass and steel), white opaque appearance, and lack of cleavage. Commonly found in riverbeds, glacial tills, and mountainous quartz veins.