A calla cut diamond setting? I would google 'calla cut diamonds' and find their official site. It is a patented proprietary cut so it should have one. The website should have a list of their authorized retailers or an 800 number you can dial for authorized retailer information.
Calla Cut Diamonds are a brand of stone (trademarked) that looks like a fat modified marquise. They are most often put in a setting that resembles a flower or butterfly.
Thanks Swingirl and iluvdiamonds2. When I was at the site they had some non-butterfly rings under the ring category. If you click on next it will take you to quite a few pages.