Diamonds are a girl's best friend! 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. You can use this during a high school geology unit.