Mercury Mist Topaz, a titanium treated natural topaz, showing the most absolutely blazing pastel blue/gold/pink/silver/whatever you've ever seen.

These stones are set into a simple Sterling Silver Post Earring Mounting, allowing the most show of stone for the least expense.  It's a good stable setting that doesn't set you back a month just to get one.  There's no reason why these stone shouldn't last you for years, and dazzle every day of it.