Rose gold

Rose gold is a gold and copper alloy generally used for specialized jewelry due to its reddish color. It is also identified as pink gold and red gold. Because it was popular in Russia at the beginning of the nineteenth century it is also known as Russian gold, although this term has become somewhat rare.
Since it is an alloy, there is no such thing as "pure rose gold"; pure gold is yellow and pure copper is reddish.
Although the names are often used interchangeably, the dissimilarity between red, rose, and pink gold is the copper content: The higher the copper content, the stronger the red coloration. A common alloy for rose gold is three-quarters gold and one-quarter copper.
Rose gold is also the name of a commonly-used finish in bell interiors of musical instruments. It consists of a very thin plating of copper over a layer of silver. No real gold is used.