Sometimes this is called agate sometime opalite, here usually the name is opalite. It comes from Norseman, W. Aust. The correct mineralogical term for this material is chalcedony with dendritic pyrolusite inclusions. These inclusions form the dendrites throughout the rock. This particular slab has a nice mix of colors right thru to the areas of reasonably clean quartz.
65 x 34 x 14mm