Rarer than diamonds and more valuable than any other coloured jewels, a fine emerald represents natural beauty at its most beguiling. Jonathan Self journeys into the lustrous world of this revered gemstone

Technicolour dream coats I SPENT much time (too ...

Researchers studied stalagmites in Postojna Cave in Slovenia ...

Astronomers are now regularly detecting planets thousands of light years from Earth – but have we missed one in our own Solar System?

Amazing answers to your curious questions

Although it’s by no means certain, scientists are slowly accumulating evidence that life once existed on the Red Planet