mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: White to milky; Luster: Vitreous to waxy; Crystal structure: Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: White to milky
Luster: Vitreous to waxy

Identified April 22, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: White to milky; Luster: Vitreous to waxy; Crystal structure: Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed from molten silica cooling in igneous rocks or as veins in metamorphic environments. These specific specimens are river-worn and weathered, likely originating from ancient quartz veins.

Uses & applications

Used in glassmaking, jewelry (as semi-precious stones), electronics (piezoelectric properties), and commonly as decorative landscaping gravel.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. These milky appearance variations are caused by tiny inclusions of liquid, gas, or both, trapped during crystal growth.

Field identification & locations

Identify in the field by its hardness (it will scratch glass) and lack of cleavage (it breaks in irregular, shell-like curves). Very common in riverbeds and pebbled beaches.