A spectacular calcite from an amazing find in Nantan (also known as Nandan), China (weirdly enough, the same locality as the meteorite in this set of auctions). The three "towers" of stacked, intergrown flat crystals are outlined around the sides by an unidentified microcrystalline mineral that fortuitously adhered to the crystal edges, making what would have been a beautiful specimen into a true jaw-dropper.