Selenites are quite common from the Naica, Mexico area, but you do not see many worldwide specimens. Here is a rare one from one of the former Soviet republics, showing the same intense glassy clarity that makes some selenites so striking. What is unusual here, as compared to the Mexican ones, is how the selenite here is nicely set on multicolored blue on red celestine matrix. You can see through the flat "windows" into its clear interior.