The colors of the rock texture seems quite different from the blender view. Does the unity scene have a colored light or is it because of the selected unity shader?
The colors may not be exactly the same due to various factors, but usually Unity likes to add a slight tint to objects and/or also likes to add more shine to them. Take a look at the material and make sure the Albedo color is fully white and you can adjust the shine manually (if using the Standard shader).
