Students can research birthstones and other gemstones. Have them identify their birthstones and share with the class. This read aloud book tells the story of Bentley's work as developer of the process of microphotography and its beginning in his Vermont childhood. It not only is germane to the study of crystals, but also points out to young children that things they are curious about at a young age can become the focus for lifelong study. Depending upon the age of your students, either read the book to them, have them read the book, or have them research William A. Bentley.
Students can create a coloring book of patterns they observed when examining the crystals they made.
You may wish to have them research photomicrographs of crystals whose special properties have been used to create color images. For younger students, have them draw a coloring page based on the patterns they observed and color them. You can Xerox the pages and have students exchange with one another. He is best remembered for his depiction of red blood corpuscles. Van Leeuwenhoek was able to draw these tiny structures only after he experimented with different simple microscope designs.