I don't know your particular book, but the societal aspect and 'stone as a new weapon' reminds me of West of Eden by Harry Harrison.
May give a lead to your book.
Crowdsource your search for the name of that thing.
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I don't know your particular book, but the societal aspect and 'stone as a new weapon' reminds me of West of Eden by Harry Harrison.
May give a lead to your book.