mineral

Quartz (Iron-stained Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white with reddish-brown iron staining; Luster: Vitreous to dull; Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Milky white with reddish-brown iron staining
Luster: Vitreous to dull

Identified July 16, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Milky white with reddish-brown iron staining; Luster: Vitreous to dull; Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Formed through hydrothermal processes or within igneous rocks like granite. This specific specimen has been chemically weathered and physically eroded into a rounded pebble shape by water or wind. Geological age can range from millions to billions of years.

Uses & applications

Common quartz is used widely in construction (sand/gravel), glass manufacturing, and electronics. Small pebbles like this are mainly of interest for amateur collecting or as landscape gravel.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Iron staining, caused by the oxidation of iron-rich fluids, often creates the orange or brown coloring seen on the surface of white quartz pebbles.

Field identification & locations

Identify in the field by its hardness (it will scratch glass) and lack of cleavage. These are ubiquitous in riverbeds, beaches, and glacial till globally.