Love your picture. I stumbled across this feature a couple of years ago. I never actually tried to photograph the chips though. Most chips have some variations but I don't remember what they were, on an individual chip by chip basis. Now you have me thinking. I will have to take out my chips and photograph them uder blacklight. Also, I haven't, but has anyone ever checked the edges under uv. maybe some do have some markings. I know I have seen a couple chips that I swear have glitter in the clay or resin, whatever they are made of. Maybe that will react to UV.