Boulder

From Freepedia

This article is about the large rocks known as boulders. There is also a city called Boulder, Colorado and other uses of the term boulder.

Image:Jumbled rocks and boulders.jpg

In geology, a boulder is a large rock, greater than 256 mm (10 in) in diameter (see grain size for standards in use). While a boulder may be small enough to move or roll manually, others are extremely massive. Some famous rock formations involve giant boulders exposed by erosion, for example the Devil's Marbles in Australia's Northern Territory.

In common usage, the term boulder is most often used to refer to large boulders, especially ones too large for a person to move. Outside of the field of geology, smaller boulders are usually just called rocks or stones.

Some people choose to climb larger-sized boulders for recreational purposes or as a method of training for mountaineering and free climbs. This practice is known as bouldering.