Here is a bottle stopper I just finished, its Bethlehem Olive wood with a Paua shell cabochon, Afghan Lapis Lazuli. They are just under 4mm each. I used one of Ruth's stainless steel bottle stoppers.
Pulled this out at work and got an order for 3 more. 2 with the semi precious stones one with just the Cab. I have not even priced it out yet, she said no worries, even told me different colors would work. I know I only have 6 more of the Lapis, but will have to dig in the box and find something else exciting to go with it.
The finish is minwax fast drying polyurethane clear gloss. I am still looking for the finish that will make me happy on these. This one has about 8 to 10 coats with 2 days cure time after last coat before I put a finger on it.