mineral

Clear Quartz (Milky Quartz pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale. Color: Translucent to milky white, clear in areas. Luster: Vitreous to waxy when water-worn. Crystal system: Trigonal. Cleavage: None, exhibits conchoidal fracture. Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Translucent to milky white, clear in areas
Luster: Vitreous to waxy when water-worn

Identified July 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed in a wide variety of geological environments, primarily pegmatites, hydrothermal veins, and igneous rocks. Smooth, rounded pebble shape results from natural water erosion in rivers or ocean beaches (or artificial rock tumbling).

Uses & applications

Used in gemstone lapidary, rock tumbling collections, decorative landscaping, jewelry making, and historically in optical instruments and electronics (piezoelectric applications).

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Ancient Greeks believed clear quartz was ice frozen so hard it would never melt, calling it 'krystallos' meaning ice.

Field identification & locations

Identified by its ability to scratch glass easily (Mohs hardness 7), absence of cleavage, and clear to milky white translucent appearance. Found worldwide in beach pebbles, gravel pits, and riverbeds.

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