Pebbles come in various colors and textures, and can have streaks of quartz and different colored sedimentary rock. Pebbles are mostly smooth but, dependent on how frequently they come in contact with the sea, they can have marks of contact with other rocks or pebbles.
Pebbles can also be found inland where ancient seas used to be covering the land, when seas retreat the rocks become landlocked. They can also be found in ponds. Pebbles can also form in rivers, and travel into estuaries where the smoothing continues in the sea.