The file 'Fake Rock Crystal 3D Printer Model' is (stl) file type, size is 31.7KB.
After having visited the breathtaking rock crystal collection at Naturhistorisches Museum in Bern, Switzerland (http://www.nmbe.ch), I tried to recreate the shapes. Turns out it's not just hexagonal stuff, especially if the goal is to make it look natural. I am still trying to achieve better results, but here's the first "stone" to start with.
crys01.stl | 93.3KB |