I am a big fan of rainbow crystals. For those of you who do not know about them, rainbow crystals are crystals that have one or multiple fractures within them that create a beautiful display of colors (a rainbow) when viewed at the right angle in the light. These rainbows are thought to help counteract negativity. Thus, rainbows are a wonderful addition to the features of a crystal for that metaphysical characteristic as well as their appearance. Rainbows are quite a common occurrence in quartz. Here are a couple of images from my etsy shop of rainbow crystals.
Next time you are looking for a crystal from a tumbled stone bin or anywhere else, I recommend looking for rainbows to add a bit of cheer to your crystal collection.