The V-Ray Rock texture generates a procedural rock pattern using two colors or texture maps.  

Uvwgen – 

Color 1 – Input for the first color texture.

Color 2 – Input for the second color texture.

Compatibility With – Allows you to match the result of the texture in Blender to that in either 3ds Max or Maya.

Max – The resulting alpha of the texture is the intensity of the texture.
Maya – The resulting alpha of the texture is the color luminescence.

Invert – When enabled, inverts the colors in the final result.

Invert Alpha –  Inverts the alpha channel if Invert is also enabled.

Color Multi – 

Color Offset – 

Alpha Mult – 

Alpha Offset – 

No UVs Color – 

UV noise phase – Specifies the UV noise phase.

Grain Size – Controls the size of the fine grain features. 

Diffusion – Lower values make the resulting texture sharper, while higher values blur the texture details more.

Mix Ratio – Controls the mix between Color 1 and Color 2.