is pebble an igneous rock?

Question

Is pebble an igneous rock, sedimentary rock or metamorphic rock?

Answer 1

Pebbles can be all 3 kinds. Pebbles are formed through erosional processes that breaks up rocks into smaller pieces and smoothens them through river processes like saltation etc. Any kind of rock can become a pebble, as long as they went through these processes, so it really depends. However, igneous rocks tends to have smaller crystles, or even no crystles at all. Sedimentary rocks are more likely to have layers of different compositions of minerals. For most of the pebbles that we can buy at a cheap price, i suppose they are sedimentary rocks.

Answer 2

All pebble means is a small rounded rock. Its probably not sedimentary as the structured layers would not make a nice rounded shape. But it could be either of the others.