Ritz - art deco modern style dinner ring
http://www.xstreetsl.com/modules.php?name=Marketplace&file=item&ItemID=1089352

Sapphire Star - more traditional styling, on gold:
http://www.xstreetsl.com/modules.php?name=Marketplace&file=item&ItemID=1087783

Both of these come packed in a little suede ring box that your recipient can have the fun of rezzing out to collect the contents themselves.