Slab of marble 17mm thick, but which was knocked over from where it was propped up against a fence and so unfortunately shattered into these pieces.
Smaller rectangular-ish piece of different marble, less colourful, 2cm thick.
Both are grimy and will look better after a wash/scrub.
N.B. Re- the photos, there are two of the larger slab, one of the pieces upside down and one with the more colourful side face up.