Most of the time, stone tools can be dated within their context. If you can date other things like charcoal within the same strata, you got the approximate date of the tool. Another good dating system is to recognise the caracteristic tools corresponding to a culture.

How do you date ancient stone tools?

There is no way to date a stone carving or artifact based on just the stone itself, because the chemistry of the situation is too variable and too complex. For example, moisture and temperature fluctuation will have a big effect on how a stone weathers.

Which animals can make and use tools?

Corvids (such as crows, ravens and rooks) are well known for their large brains (among birds) and tool use. New Caledonian crows are among the only animals that create their own tools.