In jewellery making, pure gold is often not used but gold alloys. This includes red gold, which is given a red and dark colour by the addition of copper. In addition to the fine gold, which is always the eponymous basis of red gold, and the copper, silver is also added to the alloy to obtain a certain shade. 8 carat red gold is just as possible as 14 or 18 carat red gold, the decisive factor being the proportion in the alloy. If 66.7% copper is added to 8 carat red gold, the result is a deep rusty red gold. If 14 carat gold is combined with 14% silver and 27.5% copper, the red gold becomes orange-golden. The well-known shimmer of red gold, or rose gold, comes about when there is an even higher concentration of fine gold in the alloy. This is the case with 18 carat gold with 20.5% copper and 4.5% silver. Red gold can be created by the most diverse combinations, whereby the gold content is of course decisive for the value and the copper content determines the red colour. Rose gold is a particularly noble variant of red gold. Rose gold is often simply referred to as red gold. Strictly speaking, the proportion of copper and silver in rose gold is lower than in most other types of red gold, and the proportion of fine gold, which determines the value, is correspondingly higher.
