1. Create a new document. I have used 300px by 300px but you can use whatever you want.
2. Draw a circle in the center using the circle tool with the color #828282 (hex Value). This does not need to be center.
3. Go to the direct selection tool. To do this hold down on the black arrow and a menu will come up. Move down and select "Direct Selection tool A"
4. Distort the circle to look more pebble shaped. To do this pull on the boxes and the circles. Below is what mine looks like.
5. Rasterize the layer by right-clicking on the layer in the layer selection toolbox and press "rasterize"
6. Add noise to your pebble. To do this go to: "Filter > Noise > Add Noise". This will give it a natural randomness. The settings below are best.
7. Go to the blending options of this layer ("Layer > Layer Style > Blending options") and add a bevel and Emboss. The below are recommended for the size 300x300.
8. Select drop shadow and use settings similar to below... please do not be wussy with the shadow... It adds to the effect to make it look more realistic.
9. Using the Polygonal selection tool (hold on lasso and move down to "Polygonal Selection Tool") make a line somewhere accross the pebble. Then use the Dodge tool (Key: O) scrub in the selected area to lighten. (don't let go) It doesn't have to be neat.
10. Now use the Dodge tool with a very small brush size to make dots and scratches onto the pebble... be random but don't go too ott. You can then add a background of your choosing... Here is what I have.







More Photoshop: