Jeremejevite (about $2k a carat), pronounced ye-REM-ay-ev-ite, is a colorless, sky blue or pale yellow stone, the highest quality of which comes from Namibia. In nature it occurs in small obelisk-shaped crystals and has in the past been mistaken for aquamarine. It was named after Russian mineralogist Pavel Jeremejev [Павел Еремеев] who discovered the mineral in 1883.
Kësterite, Cu2(Zn,Fe)SnS4, with a coating of Mushistonite, Huya W-Sn-Be-Deposit, Xuebaoding, Pingwu, Sichuan Province, China. The floater crystals of Kësterite are disphenoides, a crystallographic form that is not normally apparent. Size 2 x 1.9 x 1.8 cm. Copyright: Fabre Minerals