Chameleon diamonds change colour when chilled in liquid nitrogen

Chameleon diamond

Some chameleon diamonds change from grey (left) to yellow (right) when submerged in liquid nitrogen

Jae Liao

Collectors lusting after the rarest of gems have a new kind to add to their list: diamonds that change colour when made extremely cold.

These aren’t the first gems known to change colour: so-called “chameleon diamonds”, first discovered in 1866, switch their hue from greenish to either brown or yellow when heated to about 200°C or kept in the dark for more than 24 hours.

But while grading diamonds for clients, Stephanie Persaud at …

source: newscientist.com