Sandstone (Quartz Sandstone)

Physical Properties

Hardness: 6-7 on Mohs scale (due to quartz content); Color: Tan, brown, or buff; Luster: Dull or earthy; Crystal Structure: Clastic texture with visible sand-sized grains; Specific Gravity: 2.2 to 2.8; Cleavage: None.

Formation & Geological History

Formed by the accumulation and lithification of sand-sized mineral particles (primarily quartz). This specific specimen is a river-worn cobble, meaning it was shaped and smoothed by water transport over long periods in a high-energy fluvial environment.

Uses & Applications

Commonly used as a building material, paving stone, and in the manufacturing of glass. Well-rounded river cobbles like this are often used in landscaping and garden decor.

Geological Facts

Sandstone is one of the most common sedimentary rocks on Earth and makes up about 20% of all sedimentary rock on the planet. Its porous nature makes it an excellent reservoir for groundwater, oil, and natural gas.

Field Identification & Locations

Identify in the field by its 'gritty' feel (like sandpaper) and visible rounded grains. This smooth, oval shape indicates it was found in a riverbed or coastal area. Sandstone is ubiquitous in sedimentary basins worldwide.

Identified on: 4/26/2026

Mode: Standard