Yeah, Sue, I was also waiting for someone else with more knowledge to answer, but I finally gave in.
Mary, another thing to keep in mind is that not all translucent marbles are akro. Not even all translucent marbles with "fire" inside -- the orange glow you see when you hold them up to the light.
For instance, Champion and I think maybe even Jabo made swirls which are frequently mistaken for moonies. So, that's the clue there ... they're swirled inside. Akro Moonies and Flinties are not swirls.