Those are rare gypsum marbles, made in the 1700s in italy. Only 20-30 are known to exist, usually sell for $1,00-1,500 depending on condition and pattern. Too bad on the broken one!
Just kidding, don't swallow your tongue, I agree with Steph!
Yeah that was several years ago. My "not Alleys pile" got attacked hot and heavy and now it's down to mostly a few transparent swirls. Those might never get sorted lol.