A hard to find, colorless and terminated crystal of Topaz from Nigeria.  Nigeria's pegmatites produce a wide variety of gem minerals, yet the market is tightly controlled by local gem cartels. 

Mining is conducted exclusively for gem rough, and Nigerian dealers almost never sell on a piece-by-piece basis, meaning that if you want to buy the one complete crystal in a 1 kg lot, you would usually have to purchase the entire lot by the gram...

Obviously this makes no sense for a specimen dealer, so specimens are rarely seen, despite the relative abundance of Nigerian material and gem shows.