My understanding of the law, concerning breakage, let's say a million dollar stone, is that the craftsman cannot be held liable for breakage because it can happen to the best of jewelers, stones can break under any condition and reason.That's the law, and craftsmen are not rich, meaning they'll never come up with a million anyway.
However a CZ probably should have been replaced out of stock, a trivial expense, and never even mentioned. A craftsman job is not to stand on principal, but to make customers happy and tolerate a little abuse at times to keep a customer as long as they keep spending.
. I suspect the above previous client might have been unreasonable and threatening, therefore was no attempt to be conciliatory was pursued only because his attitude, I don't know, I wasn't there.