[FormerRep]

The marble is millions of years old (geologic time)- neither the cutting of the stone nor the inscription can be dated - no carbon to measure decay rates.

[Consort]

...neither the cutting of the stone nor the inscription can be dated...

That was my point. It doesn't matter how old the marble it. The inscription could be very recent.

[GovernmentShrinker]

Carbon-dating is hardly the only way of dating objects, especially objects only a couple of thousand years old -- was it located under an ancient building foundation or road that had clearly lain undisturbed for centuries? was there build-up of mineral and/or organic residue on the surface (including the indentations of the inscriptions) that would have taken centuries to reach its current condition? etc., etc.

[null and void]

The marble is millions of years old (geologic time)- neither the cutting of the stone nor the inscription can be dated - no carbon to measure decay rates.

No, but you can get a pretty good idea of the age of a surface by how deeply oxidation and staining penetrate the rock...