This piece of pumice has clearly been used as a tool. Two sides are smooth and flat and one rough. The flattened sides were probably used to ‘burnish’ pottery. This is the process of rubbing ceramics with stone to make the surface smooth and shiny. The rough edge would have been where the person held on to the pumice. There is some brown residue on the stone which could be remains of ceramic.
The pumice was found at Castle of Old Wick and is what archaeologists call a ‘stray find’, meaning that it was found by chance. This can happen when objects buried in the ground are disturbed by things such as construction works, farm ploughing, and animal activity.