In the planetarium in one of the halls we saw a very interesting microscope. You could see the stones. It seems to me that chalcopyrite is very beautiful.
https://pp.userapi.com/c847016/v847016945/59ebc/yqzY7Le2loY.jpg
The microscope projects the magnified image onto the screen. Very interesting and informative.
https://pp.userapi.com/c844216/v844216945/5f1b2/DFhqSv_6274.jpg