There are a few ways to test if your crystals have been dyed: One way to test if a crystal has been dyed is to put some nail polish remover on a cotton bud and then wipe it over the crystal. If the crystal starts to change color, then it's likely that it has been dyed. Another way to test for dye is to scratch the crystal with something that is high on the Mohs scale. When you do the scratch test use material higher on the Mohs scale to scratch the testing crystal. If the crystal starts to show signs of wear and tear, then it's likely that it has been enhanced.