The world’s most expensive substances command their prices for very different reasons. Some, like rare gemstones, are ...

Diamonds and emeralds might dominate the limelight, but there exists a world of gemstones so rare and valuable that they are the stuff of legends. What exactly makes a gemstone rare and valuable? It's ...

Across the hills of Kenya and Tanzania, two gemstones capture the continent’s natural brilliance and enduring mystique: Tanzanite and Tsavorite. Both discovered within a few years of each other in the ...