mineral

Quartz (specifically Citrine or Yellow Quartzite pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Pale yellow to tan; Luster: Vitreous to waxy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Pale yellow to tan
Luster: Vitreous to waxy

Identified March 7, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Pale yellow to tan; Luster: Vitreous to waxy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Formed through hydrothermal processes or within igneous and metamorphic rocks. This specific specimen is a 'river rock' or 'alluvial pebble,' meaning it was weathered from its parent vein and smoothed by the abrasive action of water (river or beach) over thousands of years.

Uses & applications

Used widely in lapidary work for tumbling and polishing, as a gemstone (if high clarity), in the manufacturing of glass and ceramics, and as a source of silicon for electronics.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Because of its hardness and chemical stability, it is the primary component of most beach sands and river gravels globally.

Field identification & locations

Identify in the field by its hardness (it should easily scratch glass) and lack of cleavage. Look for the 'waxy' appearance in rounded river stones. Found globally in almost any environment with moving water or ancient glacial deposits.

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