Shockingly sparkly crystals have made this one unusual pocket from China so famous among all calcite finds there. It is not really a calcite specimen in any case, but a "combination piece" in the most meaningful sense of the term; two otherwise nearly-valueless species combine in some unique manner to make one masterclass work of art in a mineral specimen! The coverage of iridescent pyrite makes the sharp, fine calcite crystals scintillate with colors. The colors shift and change in the light as you move around them (or move the piece). This pocket came out around 2012, with some small artisanal dealers we found unpacking it all onto raw tables in the freezing, unheated Shanghai Mineral Show in a chilling winter. I recall it clearly because it was in the huge, drafty, old former Russian Embassy near our own gallery in the Shanghai internal business district at that time (Minhang). Our breath was freezing as we handled minerals. I bought nearly all of them of any quality - at least the ones that were natural and not being painted with glue and pyrite rubble to hide dings, literally there as I sat watching. This is one of those, which has come back to me through a collection purchase. We often buy them back, when possible, as they are unequalled and modern classics of mineral collecting. It is natural and, although a few outlying crystals have small tip cleaves, in good shape overall with a pristine core display face and the major crystal being intact.