mineral and sedimentary
Quartz (White Pebble) and Sandstone (Brown/Tan Fragments)
Silicon Dioxide (SiO2) for the white pebble
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
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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.
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