In the early 1800s, a peasant farmer in the Ural Mountains of Russia discovered an unusual stone. The gemstone seemed to change color at times from green to reddish purple. In Czarist Russia, ...

Roula Khalaf, Editor of the FT, selects her favourite stories in this weekly newsletter. A 16.53-carat alexandrite and diamond ring sold at Sotheby’s for $1.92mn in ...

From astrological signs to flowers, there are many identifiers for someone's birth month. But there is none quite as beautiful or valuable as the birthstone. Each month has its own gemstone which ...

The gemstone alexandrite has the remarkable ability to change colour under different lighting. Now, scientists have found that this trick is an optical illusion that hinges on how humans perceive ...