Boulder

This article is about large rocks. For the city in Colorado, see Boulder, Colorado. For other uses, see Boulder (disambiguation).
This balancing boulder, "Balanced Rock", stands in Garden of the Gods park in Colorado Springs, Colorado, United States.
Boulder in British Columbia, Canada
Kämmenkivi stone on the Pisa hill in Kuopio, Finland
2'500 Million years old rocks on a hill in Hyderabad, India.

In geology, a boulder (or rarely bowlder)[1] is a rock fragment with size greater than 25.6 cm (10.1 in) in diameter.[2] Smaller pieces are called cobbles and pebbles. While a boulder may be small enough to move or roll manually, others are extremely massive.[3] In common usage, a boulder is too large for a person to move. Smaller boulders are usually just called rocks or stones.

  1. ^ Webster's New International Dictionary of the English Language. Springfield, Massachusetts: G. & C. Merriam Company. 1913.
  2. ^ Neuendorf, K.K.E.; Mehl, J.P. Jr.; Jackson, J.A., eds. (2005). Glossary of Geology (5th ed.). Alexandria, Virginia: American Geological Institute. p. 79. ISBN 978-0922152896.
  3. ^ "Boulder". Dictionary.com. Retrieved 24 August 2013.