mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Opaque white to translucent; Luster: Vitreous to waxy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Opaque white to translucent
Luster: Vitreous to waxy

Identified July 1, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Opaque white to translucent; Luster: Vitreous to waxy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Forms in hydrothermal veins or as a late-stage crystallization in igneous rocks. This specific specimen has been rounded and smoothed by water erosion (fluvial or glacial processes).

Uses & applications

Used as a source of silica for glassmaking, abrasive material, gemstones when high quality, and extensively in quartz watches and electronics for its piezoelectric properties.

Geological facts

Milky quartz gets its cloudy white appearance from tiny microscopic inclusions of gas or liquid trapped during the crystal's formation billions of years ago.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), white color, and lack of cleavage. It is one of the most common minerals found in the Earth's crust and is often found in riverbeds and on beaches.