Rock Identifier
Rounded quartz-rich sandstone pebble (Quartz arenite or feldspathic sandstone; primarily SiO₂ quartz grains with minor feldspar, iron oxides, and clay minerals) — sedimentary
sedimentary

Rounded quartz-rich sandstone pebble

Quartz arenite or feldspathic sandstone; primarily SiO₂ quartz grains with minor feldspar, iron oxides, and clay minerals

AI-generated identification · may be incorrect

Fine- to medium-grained, pale gray-beige, matte to slightly sandy luster, rounded and smoothed by abrasion; likely Mohs hardness 6–7 overall, with visible small pores and iron-stained patches. Sedimentary clastic texture; bedding is obscured by weathering and rounding.

Identified More sedimentary
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Physical properties

Fine- to medium-grained, pale gray-beige, matte to slightly sandy luster, rounded and smoothed by abrasion; likely Mohs hardness 6–7 overall, with visible small pores and iron-stained patches. Sedimentary clastic texture; bedding is obscured by weathering and rounding.

Formation & geological history

Lithified sand deposited in a river, beach, dune, or shallow-marine setting, then cemented by silica, carbonate, or iron minerals; the pebble was later rounded by transport. Exact geological age and locality cannot be determined from the image.

Uses & applications

Mostly a natural decorative or landscaping stone, paperweight, or teaching specimen; sandstone is also used for building stone, paving, aggregate, and historically sculpture.

Geological facts

The smooth oval shape indicates prolonged water or wave abrasion rather than original rock shape. Acid reaction, if present, would suggest carbonate cement rather than a purely quartz-cemented sandstone.

Field identification & locations

Common in streambeds, beaches, and gravel deposits. Identify by gritty texture, abundant sand-sized grains, lack of interlocking crystals, and possible vinegar or dilute-acid reaction; a hand lens helps distinguish quartz from feldspar.