The gemstones listed below are the world's most expensive, as per the median price per carat. Black diamonds are a rare and expensive type of stone colored by graphite under intense heat and pressure.

Gems made this way are significantly less expensive than naturally black diamonds. Celebrities wearing black diamond jewelry are fueling the rise in popularity of this unusual stone. The Most ...

Here’s a look at the most expensive diamonds ever purchased and their current owners. Also, check out the most expensive pieces of jewelry. The Graff Pink, a 24.78-carat fancy intense pink ...