Holmium (a metal) looks fairly interesting by polarized light microscopy. http://bit.ly/2fE1Mbh
Take a peek at Aspirin under the microscope, fairly incredible! http://bit.ly/2e0qp13
Resorcinol is a benzenediol used in some chemical and medical fields; Have a peek at it under the microscope. http://bit.ly/2dnAWDc