Until recently, diamond was the hardest known naturally occurring material. But a new physical process applied to carbon has uncovered a substance that a group of scientists say is even harder.

Researchers at North Carolina State University say they have developed a technique for creating a substance they are calling Q-carbon, which represents a third phase, or distinct form, of carbon alongside graphite and diamond.

The discovery could have many applications, notably in the fields of medicine and industry. But Jay Narayan, the lead scientist on the study, has made one claim about the technique that is certain to turn heads.

“In 15 minutes, we can make a carat of diamonds,” Mr. Narayan said. A carat is 200 milligrams.

The process of creating Q-carbon — which involves concentrating a very short pulse of laser light onto carbon — can produce minuscule synthetic diamond “seeds,” which can yield gems.