mineral

Quartz (Milky or Smoky Quartz Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Translucent grey to milky white; Luster: Vitreous to greasy; Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Translucent grey to milky white
Luster: Vitreous to greasy

Identified June 13, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Translucent grey to milky white; Luster: Vitreous to greasy; Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed from cooling silica-rich hydrothermal fluids or magma, frequently found in veins. This smooth pebble shape is the result of fluvial erosion (water wear) in the Seongjusan mountain area.

Uses & applications

Commonly used in glassmaking, electronics (piezoelectric properties), and as decorative gravel or gemstone (semiprecious).

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. The location provided, Seongjusan Natural Recreation Forest in Boryeong, is part of a region known for diverse granite and metamorphic rock formations.

Field identification & locations

Identify in the field by its ability to scratch glass, its lack of cleavage planes, and its characteristic waxy or glassy luster. This specimen is a typical river-worn pebble.

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Mineral/Rock

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mineral