Sapphire studs. I don't know what treatments they had - they were a gift. They are cornflower blue. They weren't expensive but I think they're pretty. I like the square/diamond shape on the ear (depending how you wear them).
Those are so pretty! I love the opal bezel earrings, too!
I hope you won't mind me making a suggestion for the future. It might be a good idea to post all the earrings in one thread, rings in another, all other pieces in another, rather than making a separate thread for each item when you are posting many things at one time. I love seeing them all, but most people aren't going to feel like commenting multiple times. So I think more people will look and comment when the items are consolidated in just a couple of different threads. Not essential, of course, just a thought!