Charles Avery Stone Mice - Making insignificant objects important

A Stone Mouse is: ´part animal, part mineral, whose heart beats only once every thousand year´
To identify a Stone Mouse: ´one must identify its central axis, being the line which runs between its two most extreme points (A and B), the distance AB being its length. This line must be occupied by the stone at all
points along it (so a banana-shaped stone would not qualify)´
Stone Mice need to: ´possess je ne sais quoi´
Sadly once taken from the Island and: ´subject to the harsh light of Reality… the Stone-mouse becomes merely a stone that looks like a mouse´