A natural stone with a hole in the center and gift from the earth to the lucky finder.
A totally throw away .. cannon fodder ..shove it in the mouth of the monster and run for it type of character. Useful though for ‘taken with a pound of salt’ information and running small unsavory errands.
What if casting magic changed (for a few hours or days depending on the strength of the spell) the colour of the skin of the spellcaster? It could lead sadly to a very racist world to rp in.