You may have seen vivid blue diamonds and wondered if they were real. And if real, do they occur naturally?       At Amidon we offer a variety of beautiful designs made with blue diamonds. Here’s a little background info about these amazing gems.   Formation   It takes extreme pressure and heat to form diamonds. The diamonds we wear in rings and bracelets now formed about 100 miles beneath the earth’s surface millions of years ago. Molecules of carbon dioxide crystallized and became the stones we know and love. But to get a colored diamond, extra elements must be there when the diamond forms. Blue diamonds are blue because a big amount of hydrogen or just a little boron was present at formation time.     Rarity   Just how rare are blue diamonds? Pretty darn rare. Colored diamonds are generally rarer than clear. And blue are rarer than champagne or yellow diamonds. More intense blue stones are more desirable than lighter colors. And, of course, the bigger the more valuable.   Location   You can find blue diamonds in only a few places around the world. In South Africa, blue diamonds are mined from the Cullinan mine. The Argyle mine in Australia also has blue diamonds, as did the Golconda mine in India.   Heat         Because blue diamonds are so rare, some clear diamonds are heat-treated to turn blue and meet the demand. These are real diamonds, but not natural blue diamonds. Diamonds that were blue to start with are termed “natural blue diamonds” and it will say so on a GIA certificate. The price difference will also reflect which diamond was born blue.