Hi. I had a stone in udk that worked fine, but wanted to redo the uv and texture. When i imported it again the mesh looked terrible. The model has only one smoothing group!
Cool idea! Do you have a concept or any reference you're working off of? The thing that's standing out to me is that it looks more 'lumpy' rather than carved. Check out how sharp the edges are on these pieces: https://warrenscherich.com/large-stone-sculptures
The stones cause use more depth, they seem still a bit too flat, that and the lighting, but other then that, it looks pretty solid, keep up the good work