Tried recreating this cast concrete material. It's not too far off to my eyes, but getting the colours to match with the catalog is a pain. Might be a worthy challenge to anyone who wants a good collection of concrete colours now KeyShot wants to play with ArchViz a little more :)
http://kornegaydesign.com/wp-content/uploads/2013/01/davis_colors_chart.pdf
Martin
Like the second shot, doesn't look like Cast Concrete though, more like stone or baked mud...
What I think you've found there are some Stone Age artifacts
J
It's partly colour and partly light, but they do a purply brown coloured one as above but it's a toughy to get the colours to match.
Martin