sedimentary

Quartz Pebble

Crystalline Silica (SiO2)

Hardness: 7 on Mohs scale; Color: Tan, orange, or peach-tinted; Luster: Waxy to dull (weathered); Crystal structure: Trigonal/Hexagonal (microcrystalline); Cleavage: None; Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Tan, orange, or peach-tinted
Luster: Waxy to dull (weathered)

Identified July 16, 2026More sedimentary →

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Physical properties

Hardness: 7 on Mohs scale; Color: Tan, orange, or peach-tinted; Luster: Waxy to dull (weathered); Crystal structure: Trigonal/Hexagonal (microcrystalline); Cleavage: None; Specific gravity: 2.65

Formation & geological history

Formed through the weathering and erosion of quartz-bearing rocks like granite or sandstone. It has been physically rounded by water transport in a river or coastal environment, likely during the Holocene or Pleistocene epochs.

Uses & applications

Commonly used in landscaping, road construction as aggregate, aquarium decor, and as a low-cost material for rock tumbling or beginner lapidary projects.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. These specific rounded shapes are often called 'river rocks' and their smoothness is a direct result of the energy of the water that transported them.

Field identification & locations

Identify in the field by its hardness (it will scratch glass or steel) and its rounded, water-worn exterior. It is commonly found in riverbeds, glacial tills, and beaches worldwide.