Beware of dentists bearing candy. Especially rock candy. A few years ago, Dr. Joe Daugherty, an oral surgeon from Lexington, Ky., was showing some nurses how he makes rocks look like food, in this case a box of chocolates. "Before I could stop her," recalls Daugherty, "one woman bit into a piece. It cracked her tooth. I fixed it, free, of course."

Despite such risks, Daugherty, 65, has been converting rocks into fake food for 18 years, ever since a patient showed him a hunk of flint that looked just like a baked potato. Daugherty wrapped the rock in tin foil as a joke, liked the effect and decided to try other stones. Since then he has cut and polished quartzite into french fries, agate into sliced ham, garnets into Coca-Cola and amethyst into a glass of wine. His "stone cold meal" now includes dozens of geological morsels and weighs about 300 pounds.

Some people think the dentist is off his rocker, especially since he also hangs teeth on his Christmas tree and collects human gall stones. But both Daugherty and his wife, Elizabeth, are glad he unearthed his unsavory specialty. "I feel sorry for people," he says, "who don't have a hobby."