How to determine age of stones (and other inorganic matter)?
The question being asked, I believe, is the age of the inscription or statue rather than that of the material from which it is made.

The answer, though, is that it is quite difficult to do on the basis of a single stone object. If it is found in situ, then the age of surrounding items may be a guide.

There are some clues to the age of stone objects, though. For example, if a stone object (e.g. the walls of Siloam's Tunnel) has soot on its surface, such as from torches, then radiocarbon dating shows a minimum age (because the soot could have been deposited some time after the tunnel or object was made).

Weathering of a surface can provide information, providing the object has been exposed to known atmospheric conditions; but a buried statue would erode differently from one on the surface.

For stones, or better, for ceramics, that have been heated, thermoluminescence provides an accurate way to measure age (or at least time since last being heated).

One indication for the age of the Egyptian pyramids is their alignment to a calculated geologic reference that changed with time due to the precession of the Earth.