Carrying fossilized poop around is a little different than carrying marbles but I can see why you would if it's from your Grandfather. Oddly enough, my wife's Grandfather gave me a coprolite he found on his Illinois farm long ago. But it's too big for pocket talisman. I've got my magic bean for that.
It's a patch, a veneered Victory-style marble, at least. I think old-timers may have referred to them as "Spots" but that term is no longer used as far as I know. It's probably older than the more common Victorys.