Earth's Rarest Mineral

What’s the rarest gemstone on Earth? Diamond? Ruby? Sapphire? Nope, none of these. It’s kyawthuite. The miners who discovered it thought nothing of it. This was in Myanmar, which produces a variety of gemstones: the Burmese ruby, sapphires, spinels, peridots and many others. They’re recovered in several ways. These miners were sifting through river gravel when they found a rough, rust-colored crystal they thought was topaz or amber. Nothing extraordinary, so they threw it in the basket to go to the local gem market. There, Dr. Kyaw Thu, a gemologist, picked it up. It was heavier than most metals. And it had a slightly metallic sheen. He bought it for a few kyats and took it to his workshop. There he began to study it—and found that it was a crystal compound of two rather rare metallic elements, bismuth and antimony. Surprised, he began to look for other specimens in the literature, and there were… none. Not a single other specimen of this mineral had been identified anywhere on Earth, ever. He submitted his finding to the International Mineralogical Association, who officially recognized it as one-of-a-kind—and named it after him: kyawthuite. If you’d like to see it, the crystal now resides in the Los Angeles Natural History Museum. What’s such a gemstone worth? Well, with no others to set a market value, it’s simply … priceless.