This is not the rock we're looking for...

Ok, apologies for the bad Star Wars joke. But it looked a bit like Darth Vadar's helmet to me, and I have Star Wars mad kids. 

Today's mono Monday - Rock. I'm working from home, and was engrossed in the work, so I'm afraid my rock is literally - rocks. Small ones, brought inside. With slate on the outside. I actually find rocks fascinating (if I'd have had the day off, I'd have gone up to Brimham Rocks). These rocks are sandstone, which have been chipped and damaged through building works, and the slate was from the original roofing tiles which fell during the works. Slate again is a form of sedimentary rock I think - hence its propensity to be sliceable, as sedimentary rocks are laid down in layers.