so
i made this edit and didnt get a chance to post it before this latest update
ohwell
im going to post it anyways
the first 2 are mine, the last is yours to compare with
what i wanted to show was how to go about making your rock look more rock like, and with some interesting indentations and forms opposed to a basic flatish rock
the first image is to show that i first blocked out how i wanted the forms of the rock to look, the second is a more final version showing abit of dithering and texturing
i chose more complex forms and such just to show how you might go about doing something like that, and to perhaps give ideas
i used only your colours
your new edit - the most recent you have posted looks alot better, and personally i feel is alot better than the black because the contrast becomes to much
amuch better improvement from your last 2.