What you are looking at is a picture of a baryte crystal growing on fluorite; the two minerals have not been cut or polished in any way, it is just the way they naturally are. Fluorite (or fluorspar) is a mineral made out of Calcium and Fluorine while Baryte is literally barium sulfate. It has an orthorombic, cubical symmetry. Absolutely stunning!
Andrei's background is in geophysics, and he's been fascinated by it ever since he was a child. Feeling that there is a gap between scientists and the general audience, he started ZME Science -- and the results are what you see today.