Diamonds are a girl's best friend! And crystal labs can be a science teacher's best friend because watching crystals develop is fascinating, and it results in such a pretty product! This activity is unique because the crystals are grown between glass slides with a sheet of polarized film so that they can be observed under a microscope later. The results are astounding and the lesson plan is thoroughly written, leaving you well prepared to lead learners. Use this during a high school geology unit.