mineral
Milky Quartz Pebble
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Opaque white; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Opaque white
- Luster
- Vitreous to greasy
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Physical properties
Hardness: 7 on Mohs scale; Color: Opaque white; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed from the cooling of silica-rich magma or precipitation from hydrothermal veins. The milky appearance is caused by tiny fluid or gas inclusions trapped during crystal growth. This specimen has been rounded by water erosion.
Uses & applications
Used in glassmaking, as an abrasive, in electronics (piezoelectric properties), as landscape gravel, and as a semi-precious stone in jewelry.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz specifically gets its color from microscopic bubbles of liquid or gas trapped within the crystal lattice.
Field identification & locations
Identified in the field by its hardness (scratches glass), lack of cleavage, and waxy luster. Commonly found in riverbeds, beaches, and mountain terrains worldwide.
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