Dr. Anne Helmenstine is About.com's Guide to Chemistry, and if I remember correctly she's also a jewelry designer. I discovered a photo gallery on her site today, all about gemstones -- how they're formed, what's in them, and how they've been used throughout history. It's a real good read for anyone who's interested in colored gems. If you like to go gemstone mining, don't miss Anne's photo tour of her trip to Hiddenite, North Carolina, where she found all sorts of gemstones, including the gem that town was named after.

More North Carolina Mining

Finding Rubies & Sapphires in Franklin

Imagine toting this 38 carat pear-shaped diamond around your neck. Sure, it's gorgeous, but the weight would be unbearable after a few hours of social time, and you'd have to take a bodyguard along for the ride (course, that might not be a bad thing, depending on the bodyguard). I think I could be perfectly happy with a one or two-carat pear instead. The diamond was once owned by Christina Onassis (do you think she ever wore it?) and sold recently at Christie's International in London, fetching a hefty $7.1 million. Christie's auctioned over forty pieces of jewelry owned by the Onassis family, with sales totaling about $13.5 million.

Take a closer look at the Christina Onassis Diamond.

_{Photo by Cate Gillon / Getty Images}