As for what to do with the piece you inherited. Sell it to someone who will appretiate it for the work of art that it is. Then use the money to buy the raw mammoth ivory which you can use in your work without having to worry about going to jail, or even worse, getting one of your customers arrested.
I think that if it can be documented as legal ivory (pre-import ban,
etc), you can certainly use it. But I don’t think it can be shipped
out of the country. It’s like how internationally legally harvested
ivory (i.e. narwhal tusks collected by native hunters) can’t be
brought into the US, but it’s fine to sell the antique ones already
in the states to buyers in the states.
And for all those people suggesting to sell it or preserve it, I
think I remember it being said that the inherited antique bracelet is
broken. Collectors generally do not like to buy broken pieces.
– M. Osedo http://www.studiocute.com