Rock Identifier
Perforated beach pebble (likely sandstone or chert) (Indeterminate siliciclastic sedimentary rock; predominantly quartz (SiO₂), possibly calcareous cement) — sedimentary
sedimentary

Perforated beach pebble (likely sandstone or chert)

Indeterminate siliciclastic sedimentary rock; predominantly quartz (SiO₂), possibly calcareous cement

AI-generated identification · may be incorrect

Smooth, water-worn brown pebble with matte to faintly silky luster and a natural rounded cavity/taphole; likely hardness about 5–7 Mohs, noncleaving, fine-grained, with variable porosity and specific gravity around 2.3–2.7.

Identified More sedimentary
Explore Perforated beach pebble (likely sandstone or chert) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

Physical properties

Smooth, water-worn brown pebble with matte to faintly silky luster and a natural rounded cavity/taphole; likely hardness about 5–7 Mohs, noncleaving, fine-grained, with variable porosity and specific gravity around 2.3–2.7.

Formation & geological history

Formed from lithified sand or silica-rich sediment, then rounded by abrasion in a river, beach, or surf zone; the cavity may reflect differential erosion around a softer inclusion or dissolved shell/clast. Exact geological age cannot be determined from the image.

Uses & applications

Primarily a decorative or collectible curiosity; similar stone is used as aggregate, landscaping material, and occasionally ornamental stone, but this individual has little commercial utility.

Geological facts

The hole appears naturally eroded rather than drilled, making it a “hag stone” or “witch stone,” a traditional folklore name for naturally holed pebbles.

Field identification & locations

Look for quartz grains or conchoidal fracture for identification; acid fizz would indicate carbonate cement or limestone. Common along rocky coasts and gravel bars worldwide.