This master marble is from Mark's Geometric series, each one of these a sweet piece of marble history! These incredible patterned marbles are made using the graal technique, with black glass layered over white and then the pattern meticulously laid on the marble and blasted away, then completed with a thick layer of crystal dipped and laid over the pattern which makes the whole thing absolutely pop in hand. The results are WONDERFUL, and these are some of the most magnificent marbles you'll ever behold! This gem here is simple....and wildly complex. So nicely done!! Mark made 2 versions of the Zipper, one goes to the right, one to the left, both available. Signed 'Matthews 2007'.