This is my collection of reference that I frequently use.
It consists of 1st hand photos I have taken on my travels, and collections of other artists who inspire me.
I hope by giving this collection to you, it may inspire you to.
UDK Rock Blending - Overview of the rock blending shader used for Caelus: The Descents Landscape.
Edge Highlights - PDF on how to use highlights to make rocks pop. Handy for anything needing edge highlights!