Material critique request

I’m creating a small collection of parameterized limestone materials. All the materials share the same parameters and all the parameters have a normalized range of 0.0 to 1.0

  • Texture, which varies the pattern of the material.
  • Hue, provide a full spectrum. Default value is .5, ± .09 around this value covers most limestone.
  • Saturation
  • Noise, softens textures

Not all value combinations will produce reasonable results. Setting Texture to 1.0 and noise to 0.0, for example, produces unsatisfactory results. In this case raising Noise above .8 begins to produce something more acceptable.
At this point I am satisfied with Limestone_1, a link for which is below. But I’m new to this game and would very much appreciate critical feedback.
Thanks

https://dl.dropboxusercontent.com/u/234662328/Limestone_1.blend