This slab is very cool. It is druzy citrine quartz on chalcedony, and it has the feel of a topographical map. It is more 3D in person that the photo can show. I don't know the weight as it is too heavy for my carat scale. The dimensions are 44 x 45 x 12mm deep. At the thinnest point it is probably only 2mm deep or less. The 12mm depth comes from the "hill" in the background.
This can be ground to a specific shape for jewelry, or it would make a fabulous collector's piece as it is. The crystals are tiny and this creates a shimmering effect under most types of light. Sunlight in particular really lights this up, or fluorescent tubes also do a very good job showcasing the glitter.
This auctions starts at .25BTC and the bid incrememnt is .25BTC