mineral

Quartz Pebble (Geode Fragment / Druzy Cavity)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale. Color: Translucent grayish-tan with microcrystalline quartz druze. Luster: Vitreous to waxy. Crystal structure: Hexagonal/trigonal. Cleavage: None (conchoidal fracture).

Hardness: 7 on Mohs scale
Color: Translucent grayish-tan with microcrystalline quartz druze
Luster: Vitreous to waxy

Identified July 27, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale. Color: Translucent grayish-tan with microcrystalline quartz druze. Luster: Vitreous to waxy. Crystal structure: Hexagonal/trigonal. Cleavage: None (conchoidal fracture).

Formation & geological history

Formed via precipitation of silica-rich fluids within rock cavities or gas bubbles (vesicles), which were later weathered, eroded, and rounded by stream or beach action into river pebbles.

Uses & applications

Commonly collected as river rocks, used in landscaping, tumbling for rock hounding, and educational specimens.

Geological facts

Small cavities lined with tiny sparkly crystals inside rounded beach or river pebbles are often referred to as mini-geodes or druzy cavities, preserving internal micro-crystals despite external river wear.

Field identification & locations

Look for rounded, smooth quartz-rich river pebbles that feature small open pockets or vugs containing sparkling micro-crystals when held up to direct sunlight.