sedimentary
Crescent Pebble
Weathered Quartzite or Sandstone Fragment
Hardness of 7 on the Mohs scale (if quartzite); grayish-brown color; dull to vitreous luster; massive or crypto-crystalline structure; no distinct cleavage; specific gravity around 2.65
Identified More sedimentary →
Explore Crescent Pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 7 on the Mohs scale (if quartzite); grayish-brown color; dull to vitreous luster; massive or crypto-crystalline structure; no distinct cleavage; specific gravity around 2.65
Formation & geological history
Formed through mechanical weathering and natural erosion processes, where a piece of resistant rock has been shaped by wave action or river tumbling into a distinct crescent or sickle-like shape over thousands to millions of years.
Uses & applications
Used primarily as a decorative display specimen, curiosity piece, or for rock tumbling and lapidary arts.
Geological facts
Naturally shaped rocks like this are often referred to as 'ventifacts' or 'concretion fragments' depending on how they were eroded, capturing the imagination of collectors due to their uncanny resemblance to man-made or symbolic objects.
Field identification & locations
Found along riverbeds, beaches, and glacial outwashes. Collectors look for naturally occurring unusual shapes that tell a story of geological erosion.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
fossil
Banded Siltstone / Mudstone Pebble
Siltstone / Argillite
sedimentary