mineral

Milky or Greenish Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Translucent greenish-white to milky; Luster: Vitreous to waxy; Crystal Structure: Trigonal (often massive in pebbles); Cleavage: None/Conchoidal fracture.

Hardness: 7 on Mohs scale
Color: Translucent greenish-white to milky
Luster: Vitreous to waxy

Identified June 13, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Translucent greenish-white to milky; Luster: Vitreous to waxy; Crystal Structure: Trigonal (often massive in pebbles); Cleavage: None/Conchoidal fracture.

Formation & geological history

Formed from silica-rich hydrothermal fluids cooling in veins or as a constituent of igneous rocks. The Seongjusan area in South Korea is known for Mesozoic-era granite and metamorphic rocks, where quartz is a primary component. This specific specimen was likely smoothed by water erosion in a stream or forest floor.

Uses & applications

Common quartz has massive industrial uses in glassmaking, electronics, and abrasives. Small river-tumbled pebbles like this are primarily collected as decorative items or for casual geological interest.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. The location mentioned (Seongjusan Recreational Forest) is part of a mountainous region in Boryeong, known for its dense forests and rocky stream beds containing various granite-derived minerals.

Field identification & locations

Identify in the field by its hardness (it can scratch glass and steel), its conchoidal (shell-like) fracture, and its lack of cleavage. Look for it in weathered granite outcrops or as smooth pebbles in stream beds.

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