The Green Phantom // check out this geometric caped crusader of Fluorite, another amazing crystal treasure posted by @therockhuntress. It a large chunk of gem fluorite with a green "phantom" zone inside it showing (very colourfully) the crystalline stages of its growth.
The inside of a Meteorite. "Fun fact: Widmanstätten patterns found inside meteorites cannot be replicated on Earth. This is because the patterns can only be formed in extremely slowly cooling nickel/iron mixtures (over millions of years) to form two different alloys: Taenite and Kamacite, that form slightly different crystal structures."