The new tomb of King Richard III in Leicester Cathedral is made of limestone from Swaledale in Yorkshire.
The limestone was formed at the bottom of a shallow sea that covered much of what was to become the United Kingdom, back in the early Carboniferous geological period.
It is coarse grained, and contains fossil remains of crinoids.
Crinoids are related to starfish and sea urchins.
They are spectacular fossils if they are complete, but that is quite unusual.
It is more common to find fragments of them in limestone.