Emerald green has long symbolized prosperity, wealth, and success, thanks to its association with the precious gemstone. Coveted for its deep hue and rarity, emeralds have adorned royal regalia ...

There are many examples in nature, including gemstones and paint pigments ... But how can one element—chromium—create the red color of a ruby and green color of an emerald? Rubies and emeralds have ...

One feature of compounds made with transition metals is their intense colour. There are many examples in nature, including ...