mineral

Quartz Pebble (Geode Nodules / Stream-Rounded Quartz)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale. Color: Off-white, grey, milky to translucent. Luster: Vitreous to waxy when weathered. Crystal System: Trigonal. Cleavage: None (conchoidal fracture).

Hardness: 7 on Mohs scale
Color: Off-white, grey, milky to translucent
Luster: Vitreous to waxy when weathered

Identified July 28, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale. Color: Off-white, grey, milky to translucent. Luster: Vitreous to waxy when weathered. Crystal System: Trigonal. Cleavage: None (conchoidal fracture).

Formation & geological history

Formed through precipitation of silica in cavities within igneous or sedimentary rocks, or as quartz veins that were subsequently eroded and rounded by water action in rivers, streams, or glacial processes.

Uses & applications

Used primarily in lapidary work (tumbling, cutting), as decorative garden stones, in silica glass production, or cracked open by collectors looking for internal geode cavities.

Geological facts

Many rounded quartz nodules look like ordinary stream rocks on the outside, but can harbor hollow cavities lined with sparkling quartz, amethyst, or agate crystals inside.

Field identification & locations

Identified by its high hardness (scratches glass/steel easily), rounded shape, and waxy or sugary texture. Commonly found in stream beds, gravel pits, glacial till, and desert wash regions.