mineral and sedimentary

Quartz (White Pebble) and Sandstone (Brown/Tan Fragments)

Silicon Dioxide (SiO2) for the white pebble

AI-generated identification · may be incorrect

Hardness: 7 (Quartz); Color: Milky white, reddish-brown, tan, grey; Luster: Vitreous to earthy; Crystal structure: Hexagonal/Trigonal (Quartz); Cleavage: Conchoidal fracture

Hardness: 7 (Quartz)
Color: Milky white, reddish-brown, tan, grey
Luster: Vitreous to earthy

Identified June 27, 2026More mineral and sedimentary →

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Physical properties

Hardness: 7 (Quartz); Color: Milky white, reddish-brown, tan, grey; Luster: Vitreous to earthy; Crystal structure: Hexagonal/Trigonal (Quartz); Cleavage: Conchoidal fracture

Formation & geological history

Formed through various geological processes including igneous crystallization and sedimentary deposition. The rounded quartz pebble indicates water erosion in a high-energy environment like a beach or riverbed.

Uses & applications

Quartz is used in glassmaking, electronics, and as decorative stone. Sandstone is used in construction and as landscaping material.

Geological facts

Quartz is the most abundant mineral in the Earth's continental crust. These specific specimens are rounded 'beach pebbles' which have been naturally polished by the action of sand and waves.

Field identification & locations

Identify quartz by its hardness (cannot be scratched by steel) and translucency. Sandstone can be identified by its grainy, sand-like texture and visible bedding planes. Commonly found on coastlines and mountain streams.