I purchased these marbles on ebay under the heading, UV REACTIVE CHAMPION LIGHT AMBER CRACKLED (FRIED MARBLES). I looked up fried marbles to see that they are created when someone heats marbles to a very high temperature and then quickly cools them in water. The glass will crack, but if done correctly the marble will stay together. They are used for decorative purposes.
I’ve researched why some yellow marbles glow orange under UV light and have found 2 possible reasons: One is that they contain manganese. The second is that they contain cadmium and selenium. I’m not sure which element was used to create these marbles, but either way, they fluoresce under UV light.