Here is a quick and easy rough stone texture. Start
with a new grayscale image. Make sure your color chips are set to the
default (Black foreground, White Background).
Now, Choose Filter/Render/Difference Clouds.
Next, apply Image/Adjust/Equalize.
Now, Apply Filter/Stylize/Emboss, we used settings of 135,3,300
If
you apply Image/Adjust/Equalize again you can get an almost lunar
mountain texture and if you invert it you get lunar valleys.
If
you want to add a little color to the stone you can change the
Mode to RGB mode. Then, if you choose Image/Adjust/Hue and
Saturation and check the colorize box and play around with the sliders,
you can change it's color.
