You use the cube on a piece of alien nebulite which can be obtained through the boxes which drop from select mobs. The cube then randomizes the level of the nebulite. Thus,the higher the level,the better the stats the nebulite gets,and the lower the level,the worse the nebulite is. The possibilities of the nebulite are pretty much the same as potential except I've yet to see % stats from nebulites. Although,it is possible for nebulite to grant weapons/equips Decent skills as most screenshots show. To use the nebulite that results from the box,simply socket your equip through the socketing NPC,Bo, that can be located in almost every major town.