I've noticed that these magnified pictures are relatively new in your gallery (judging by the date of posting). I like that you've moved a bit away from black and white photos (even though they have their own charm that colors cannot produce), and would love to see more of these (yes, imma color enthusiast )!
Aw, thanks! The really old stuff (before December 2011) was all stuff from my high school photography class, many moons ago. The move into color earlier this year represents moving away from my B&W comfort zone. I appreciate the kind words. :]
Shortish explanation: The microscope has two pieces of polarizing film, one at the bottom and one at the top of the microscope. The bottom polarizing film makes the light rays go all in one direction. They then pass through the mineral and get bent in various directions. The light then passes through the top polarizing film, which only lets certain wavelengths of light through. Finally, the light reaches your eye. All minerals have unique ways that light passes through them, and allow for identification under a microscope.
tl;dr: A microscope did it and I just took a picture of it. :]