mineral

Milky Quartz/Gray Quartz Pebble

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale); Color: translucent white to smoky gray; Luster: vitreous to waxy; Crystal structure: Trigonal (hexagonal system); No cleavage; Conchoidal fracture.

Hardness: 7 (Mohs scale)
Color: translucent white to smoky gray
Luster: vitreous to waxy

Identified July 7, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: translucent white to smoky gray; Luster: vitreous to waxy; Crystal structure: Trigonal (hexagonal system); No cleavage; Conchoidal fracture.

Formation & geological history

Formed from silica-rich hydrothermal fluids in veins or as a major constituent of igneous rocks. This specific specimen is a water-worn river or beach pebble, shaped by mechanical erosion over thousands of years.

Uses & applications

Quartz is used in glassmaking, electronics (as a piezoelectric material), abrasives, and as a popular collecting stone for beginners.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz gets its cloudy appearance from microscopic inclusions of fluids or gas trapped during crystal growth.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), lack of cleavage, and rounded, smooth surface if found near water. Extremely common in riverbeds and mountainous regions worldwide.