A thin crust of gibbsite, an uncommon aluuminum hydroxide, is emplaced on a neat 3-dimensional matrix. The spheres are lustrous, slightly translucent and reach 5 mm across. This new find is possibly the world's best of species for intensity in coloration. Very pretty material! Very lightweight. This was among the larger of the better-quality pieces I saw for sale in a whole table of the pocket, laid out at the Shanghai show in April 2012. Some small areas seem to have a thin layer of a glossy, clear mineral (clear gibbsite, aragonite, or maybe hyalite opal) coating some spherules.