At 7.5 mm, the larger crystal here is at the maximal size for the species. Tsaregorodtsevite is a very STRANGE mineral that is made up of AMMONIA with nitrogen, and an aluminosilicate compound. I recall when Fersman Museum started selling their extras in 1991, this was one of the most coveted of all rare species that came out the doors from their various expeditions. I got some directly at the time from curator Dmitriy Belakovskiy, who has himself been to this remote location on at least one expedition. I assume this specimen came form the same source, the only source so far as I know. In fact, I bought this piece from him at Tucson 2008, surprised to see another turn up after so long. The perch on a quartz cluster makes the display here particularly good - usually these are on flat gray rocks. (TYPE and ONLY LOCALITY)