There is a condition called Jejunoileal diverticula which can form enteroliths which are very light in colour consisting mainly of pus. I note your post from 3 to 4 years ago where you show a picture of your stool with a white occlusion which appear to be the contents of a diverticulum. The discharge can precipitate in the ilium where in forms a more solid "polished" enterolith such as your picture shows.
A simple search for Jejunoileal diverticulum may give you more information.