Green gold alloys are made by leaving the copper out of the alloy mixture and just using gold and silver. It actually appears as a greenish-yellow rather than green. Eighteen karat green gold would therefore contain a mix of 75% gold and 25% silver (or 73% gold and 27% silver). Fired enamels adhere better to these alloys.
Green gold was known to Lydians as long ago as 860 BC under the name electrum, a naturally-occurring alloy of silver and gold.
Cadmium can be added to gold alloys in amounts of up to 4% to achieve a green color. The alloy of 75% gold, 23% copper, and 2% cadmium yields light-green 18-karat gold. The alloy of 75% gold, 15% silver, 6% copper, and 4% cadmium yields a dark-green alloy. Cadmium is, however, highly toxic.
Read more about this topic: Colored Gold
Famous quotes containing the words green and/or gold:
“Green, green is El Aghir. It has a railway station,
And the wealth of its soil has borne many another fruit:
A mairie, a school and an elegant Salle de Fetes.
Such blessings, as I remarked, in effect, to the waiter,
Are added unto them that have plenty of water.”
—Norman Cameron (b. 1905)
“The award of a pure gold medal for poetry would flatter the recipient unduly: no poem ever attains such carat purity.”
—Robert Graves (1895–1985)