In 1957, two deep red stones donated to the Natural History Museum in London were found to be totally new to science. After analysing a small slice from one crystal, the new mineral was named Painite after the original donor – a man called Arthur Pain, who had first thought the gem was ruby since it was red in colour.

The chemical makeup of this new mineral was found to be calcium, zirconium, boron, aluminium and oxygen. To this day, Painite remains one of the rarest minerals on Earth – in fact, until 2001, only three Painite crystals were known to exist. Since then, further discoveries have produced many more – nevertheless, its rarity means this gemstone is usually worth between $50,000 - $60,000 per carat.