Like all of Mark's UV marbles, this one is made out of 100% uranium glass, and thus it lights up like a Christmas tree on fire when you put a black light on it. Seriously, it is unbelievably bright! Usually when I take the black light pics, I have to set the exposure to either 4 or 8 seconds in order to get enough ultraviolet light in there to light up the UV glass for a good shot. But with Mark's marbles, even ONE second is too much, and I have to set it to one quarter of one second in order to get the brightness down to a level where we can still see inside the marble! Truly amazing stuff!!

This marble is from Mark's skull series, and has an air trap skull inside of it. It looks way better in hand, as the skull has this eerie shine to it, muhuuwaahahaaaaa!! Mark made each skull unique, so every one is slightly different. Awesome collector piece here, large and in charge!! Mark has basically run out of his good UV glass and isn't sure if he'll ever get another good batch. These could very well be some of the last of his UV marbles, and these are certainly the last of the UV skull marbles, so don't miss out! Signed 'Matthews 2011'.