My beloved and I had a gorgeous blue moonstone ring made at Skylight Jewelers http://skylightjewelers.com/ as an engagement ring. They show lots of carved ones on the website, but we got a plain one.

We've had several other semi-precious pieces made there over the years and have purchase other beautiful pieces there as well. The owner and staff are talented and lovely people. It's located near Downtown Crossing on School Street, behind the Parker House Hotel.