Here you can find a lot of various huge cracked cliff models and example gathering.
Triangle counts:
Cracked rock big 1 - 13700 tris
Cracked rock big 2 - 8900 tris
Cracked rock mid 1 - 3400 tris
Cracked rock mid 2 - 3750 tris
Cracked rock small 1 - 580 tris
Cracked rock small 2 - 2200 tris
Cracked rock small 3 - 2900 tris
Cracked rock small 4 - 2080 tris
Cracked rock small 5 - 1450 tris
Cracked rock small 6 - 3800 tris
Cracked rock flat 1 - 2900 tris
Cracked rock flat 2 - 2200 tris