Protecting from stone swapping allegations

Hello,

I sell tension set rings on the internet. I have started suggesting
that customers send me their own diamond stones for use in the
tension setting. I have read about how to counter allegations of
over the counter stone swapping, what about over the internet
allegations? Now my question is: How can I assure the customer that
the stone they mailed me is the stone they received back.

Any help will be appreciated.
Johan

How can I assure the customer that the stone they mailed me is the
stone they received back. 

Just my personal response, but no way would I send you a diamond to
be mounted. I have no idea who or what you are, but the business you
(we) are in depends on trust.

I can’t think of a method to assure another that the stone they sent
to you is the stone that will be returned.

There are lots of internet scams. Face to face instills confidence in
a way that the procedure you propose doesn’t.

KPK