They come from Tudun, a pegmatite in Nasarawa state, known in the past for its fine tourmaline production. The mine was abandonned for several years, but now is active again. While digging a new pit, the miners found a pocket of large vayrynenite crystals close to the surface.
The material made its way to Bangkok and I've heard of clean faceted stones of several carats already floating on the market.
