I really like depth and volume of the rocks you have going on. The color variation is subtle but works very nicely. The fine detail you have on the dirt adds a lot of nice interest on an otherwise plain surface. This piece is almost complete. I think right now the thing that will help your piece the most is adding a little more depth to your shadows. Your highlights and midtones are really well developed, if you give that same treatment so the shadows, you'll add even more depth and volume to your piece. Pop in a few core shadows around some of the edges and that will help ground the rocks a little better.Good work!-B
I love how your spec turned out. Looks good on the render especially.