These were a special request from my friend who had a birthday in August (who can resist a birthday girl’s wishes?) She wanted something like something she’d seen on etsy or in a magazine, where it was a small bisque fired pendant used as a personal diffuser for aromatherapy. She said it didn’t matter what they looked like. I think the one in the picture had a small coin-shaped piece of clay with a design embossed in it. These are high-fired non glazed black mountain. I haven’t used them, since I don’t have any essential oils, but I don’t see why they wouldn’t work.