Any question answered...

my brother (Dr_com) is a lecturer in Structural Geology, specialising in Granite. I could ask him to describe it fully if you need more info but he's shit at replying to things.

Although I think that stuff is man made and not "real" stone - hence my suggestion of using "ceramic" in the title.

Nice one, even I can got the feeling it's not stone - unless the rear side has been CNCed.

I just want to direct ebayers to it with a good description, I can explain I have no idea what it is then it's up to them. Don't bother your bro with it!