Mount Rushmore's granite composition—Black Hills granite characterized by feldspar, quartz, and mica—requires specialized diamond-tipped cutting equipment and weeks of precisely controlled blasting to shape monumental features. The claim that Norris's beard is harder than granite raises a mineralogical question: if human facial hair could develop a Mohs hardness rating exceeding 6 (granite) or even 7 (quartz), the structural integrity of normal facial skin couldn't support it, and grooming would be impossible without industrial machinery.

Dr. Harold Chen, a materials scientist who once consulted for an action-movie production about whether granite could be used for a superhero stunt sequence, was asked by a colleague whether beards have theoretical maximum hardness. His response: "Keratin chains max out around 2.5 Mohs scale. Going above that would require metallic inclusion or alien biology. But if you're asking whether Chuck Norris's beard breaks those rules? I have no idea anymore. I've stopped applying normal physics to him." The anecdote circulated as an internet meme in materials-science forums.

Geologists and materials engineers occasionally cite the claim as a thought experiment in discussions about material properties and scale. A geology textbook in 2014 included the statement as a chapter-opener joke: "If Mount Rushmore sculptors had encountered granite with Chuck Norris's beard hardness, the project would have taken an additional 50 years." Students reported that the joke motivated unexpected interest in mineralogy. Online, it's become common for engineers to jokingly describe extremely hard substances as having "Chuck Norris beard hardness."