Weathered sandstone pebble

Fine- to medium-grained, rounded pebble with a matte earthy-brown surface from iron-oxide staining; composed mainly of quartz with feldspar and clay minerals. Hardness is roughly 6–7 for quartz grains, but the cement may be softer; no obvious cleavage, generally low to moderate luster, and specific gravity about 2.2–2.7.

Formed when sand was deposited, compacted, and cemented, then rounded by stream or beach transport and weathered at the surface. Its exact geological age cannot be determined from the photograph.

Common sandstone is used as building stone, paving, aggregate, and occasionally decorative material; this small specimen has mainly educational or modest collecting value.

Iron oxides produce the ochre-brown color, while abrasion has smoothed the corners. The granular texture distinguishes it from many dense volcanic rocks, though lighting obscures fine details.

Look for visible sand grains, gritty texture, and weak layering or cement; a steel nail may scratch softer cement but quartz grains resist scratching. Sandstone pebbles occur widely in streambeds, beaches, and glacial deposits.