But thats purposely added and cullet is used at Jabo. I agree that aventurine was pretty much accidental "back in the day" when batch made glass was used. Peltier sure did nail it though, and (to me anyways) finding out that they repeatedly used the same formula to get the "sparkle" would be the least surprising new piece of evidence to surface if it were to.
JVV, that is out of this world!