McMum had a little cardboard cigar box that she kept pearls in. Not a pearl necklace, but pearls that she had found in mussels she and McDad collected from the bed of the river Fleet near Gatehouse in Galloway. They were tiny and knobbly but quite definitely pearls; some of them we had almost broken our teeth on when we ate the mussels.
Once she found a minute crab, a perfect specimen entirely covered in pearl. It lived in the box too, until one day it completely disappeared. We never found out what happened to it.