Noun
a gold alloy (at least 14 karat gold with silver or silver and cadmium) that has a green appearance
Source: WordNetMedals made before 1980 were struck in 23 carat gold, and later from 18 carat green gold plated with a 24 carat gold coating. Source: Internet
For several decades the medals awarded with the Nobel Prize have been made of gold-plated green gold. Source: Internet
It has also been produced artificially, and is often known as green gold. Source: Internet
Since then, they have been struck in 18 carat green gold plated with 24 carat gold. Source: Internet