I've read about vaseline glass, which glows bright yellow to yellow/green under a black light. I believe it may have some uranium or some other element which causes the glow. Please correct me and educate me on that if I am wrong. But, I've also discovered at several of the marbles in my find which glow orange/red under black light. What causes that? There is at least one which appears a very dark translucent (green black) with light colored swirls internally (to the naked eye), then under black light, there is the orange/red glow imbedded. Fascinating. What's this? Anyone?