As of autumn 2006, amazing artists, such as KENAN TIEMEYER, DREW FRITTS, BRAD BRANDOLINO (the Matrix Man), KEVIN O'GRADY,
DAVID SALAZAR, etceteras, expand the
possibilities to a frenzied degree. Of note, the fume technique is causing havoc among addicts, at the moment. Bidding war usually occur on Ebay and other sites. Uranium inclusion is always a welcome diversion. And optical is rare, and I am not talking about vortex, either. A huge marble, 2.60 inches in diameter or more, is a must.
Personally, I stay away from a drab, puny mib, something that is less than 1.30 inches in diameter, especially with morose colors. And unintentional bubbles in the design vex most marble collectors, and these are usually a sign of carelessness in one's work, or even lacking in skills -- an amateur, perhaps?