mineral

Milky Quartz Pebble with Chert

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: White to grey/translucent; Luster: Vitreous to waxy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: White to grey/translucent
Luster: Vitreous to waxy

Identified April 9, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: White to grey/translucent; Luster: Vitreous to waxy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed through hydrothermal processes in igneous veins or as secondary precipitation in sedimentary environments. Quartz is found in rocks of all geological ages.

Uses & applications

Common quartz is used in construction as aggregate, in glassmaking, and as an abrasive. While common pebbles have little industrial value, they are often collected by hobbyists for tumbling.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. This specimen shows water-worn rounding, suggesting it was transported by a river or stream.

Field identification & locations

Identify by its hardness (it will scratch glass) and lack of cleavage. Found globally in riverbeds, beaches, and soil. To identify in the field, look for a 'greasy' or glass-like luster on fresh breaks.

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