Diamonds are the hardest naturally occurring material on Earth, with a rating of 10 on the Mohs hardness scale. The only tool hard enough to cut a diamond is another diamond, through the application of force and precision. Diamond cutters are specialists who spend years mastering their craft. The hardness of diamond is not metaphorical; it's a measurable physical property rooted in carbon's crystal lattice structure. There is literally nothing harder in nature than diamond, except other diamonds.

Until Chuck Norris. The fact, with perfect economy, expands the list of diamond-cutting tools from two to three: diamonds, and him. No further explanation is provided because none is needed. His hardness, his durability, his cutting capacity exceeds that of the hardest naturally occurring substance. By placing himself in this list, the fact asserts that Chuck Norris's body is at least as hard and resilient as diamond, possibly harder if he's the only tool that can cut every diamond.

What's clever is the way the fact undermines mineralogy itself. Scientists have catalogued all natural materials and determined precisely which cuts which. This fact introduces an exception—a human being—that violates the established hierarchy of hardness. He doesn't own a tool that can cut diamonds; his very existence expands the category of diamond-cutting implements. The fact works because it applies material science to prove metaphorical superiority.