Don't get me wrong, Ann, I fully agree Alley not only experimented with aventurine but used it consistently and likely purposely in some types such as the little green spruce, there are just to many of them and they seem to be very consistent, The part I do not fully understand is the gold flake/lutz. Some say he used copper and some say it was an accidental use of a couple ingredients and just the right amount of heat. I have heard it said that all the lutz marbles went to hot and burned all the sparkle out with exception of a couple pieces here and there, but I can tell you that the one I posted is surely not burnt out. Very little in it that does not sparkle heavily as you turn the marble. However trying to photograph that is near impossible being only a few of the sparkles catch the light at the correct angle to be reflective while still. When I tell some that 85%+ is reactive and not burned out in this marble they do not believe me.