Mineral

Quartz Pebble (Geode-like)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Tan/brown exterior with white crystalline interior; Luster: Vitreous to waxy; Crystal structure: Hexagonal; Cleavage: None; Specific gravity: 2.65.

Hardness: 7 (Mohs scale)
Color: Tan/brown exterior with white crystalline interior
Luster: Vitreous to waxy

Identified March 30, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Tan/brown exterior with white crystalline interior; Luster: Vitreous to waxy; Crystal structure: Hexagonal; Cleavage: None; Specific gravity: 2.65.

Formation & geological history

Formed through hydrothermal processes or silica-rich water precipitating in rock cavities. These are often weathered out of sedimentary layers or riverbeds. Geological age varies from millions to billions of years depending on the host formation.

Uses & applications

Common specimens are used for landscaping, as aquarium decor, or as introductory samples for rock hounding. Industrial quality quartz is used in glassmaking, electronics, and abrasives.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. This specific specimen shows a 'druzy' center where small crystals grew inward toward a hollow space.

Field identification & locations

Identify in the field by its ability to scratch glass and lack of reaction to acid. Look for water-worn pebbles in stream beds or gravel pits that appear 'hollow' or show crystalline fractures.