Pebble
From Wikipedia, the free encyclopedia
- For other uses, see Pebble (disambiguation).
| Image:Wave Retreating from Pebbles.jpg |
A pebble is a clast of rock with a grain size of 4 to 64 millimeters based on the Krumbein phi scale of sedimentology.
A rock made entirely of pebbles is termed a conglomerate.
Pebble tools are among the earliest known man-made artifacts, dating from the Palaeolithic period of human history. They have been found at Olduvai Gorge (1.85 million years ago) and at Longuopo in China (1.8 to 1.5 MYA). Pebbles have many uses, such as weapons, floor coverings, etc.
