This texture was generated in Filter Forge, a Photoshop plugin that allows you to create your own filters.
Stonewerx is for creating small scale surfaces
Bump% adds black until there is no bump
Specular% adds black until there is no specular
Curve adjust switches between the following curves
1-Flat
2-Noise
3-Gaussian
4-Gain
5-Stairs
Curves are applied to colour and noise
make sure you check the bump and specular map after making any adjustments. Changes can sometimes move one of these channels out of range.