Raw cut geode rings are just too lovely! There are so many to choose from (amethyst and pyrite being my personal favourites) I abosolutely adore them, they're a great accessory and definately a talking piece, even better...you can find them everywhere!
Gary Pepper Vintage does some beautiful ones in her new online store
If you want a bargain though head to Etsy.com to find beautiful, handmade rings of all diffrent stones, colours, designs and sizes. That's where I've been lusting over my beauties, this one in particular by fiveandtwo has me salivating.