Rose Gold :: Copper in Rose Gold Alloy :: Rose Gold Jewelry :: Rose Color Jewellery :: What k is Rose Gold

Rose Gold :: Gold and Copper Alloy

The precious metals of silver and copper are blended in an alloy with pure gold to create rose gold. Gold and copper are the only coloured metals, all the rest are silverish in colour. Pure gold (24k) is always yellow, and pure copper (Cu - cuprum) is a brick red colour.

Rose gold does not occur in nature. Rose gold is made using a mix of pure gold with alloys including copper. Rose gold has a very subtle and delicate colour that intensifies with age. Rose Gold has a warm elegance that's been appreciated for centuries.

Rose gold is also known as pink gold or red gold. Although the names are often used interchangeably, the difference between red gold, rose gold, and pink gold is related to the copper content in the gold alloy.

Difference between Rose Gold, Pink Gold and Red Gold

The higher the copper content in the gold alloy, the stronger the red colouration. Common 18k rose gold alloy constituent quantities are

75wt% gold and 25wt% copper .
75wt% gold, 21wt% copper and 4wt% silver.

The highest karat version of rose gold is known as crown gold. Crown gold is 22 karat.

Rose Gold Karatage

22 Karat Rose Gold
A 91.6wt% gold, 8.4wt% copper alloy with a slight rose blush.

18 Karat Rose Gold
An alloy varying from 75wt% gold, 25wt% copper to 75wt% gold, 16wt% copper, 9wt% silver alloy.

14 Karat Rose Gold
An alloy made of copper, gold, & silver, usually in a 58.5wt% gold, 32.5wt% copper, 9wt% silver ratio.

9 Karat Rose Gold
An alloy of 42wt% copper/, 7.5wt% gold, 20wt% silver.
Low carat Rose Gold may contain zinc and or nickel.

For more information on karatages see Gold Grade by Humagaia.

Rose Gold Alloy Colour Variations

Rose gold may also vary quite a lot in colour depending on the amount of copper mixed with the gold, the higher the copper content the more reddish the colour.

9k rose gold has a darker rose-copper color than
18k rose gold which has a more subtle rose colour.

Rose Gold Alloy Properties

Rose gold:

Is a soft metal similar to yellow gold
It has a hardness of 2.5 on the Mohs scale,
It has a Vickers Hardness (VHN or HV) of 120.
Rose gold has a melting point of around 240º C.
9k rose gold has a darker rose-copper colour than 18k rose gold
which has a more subtle rose colour.
14k rose gold is slightly softer than 14 carat yellow gold due to the increased amount of the softer metal copper.

Mesoamerica

Tumbago

When the Spanish invaded pre-Colombian Meso-America and the rest of South America they were in search of gold for their royal family. What they found was an alloy of gold and copper that has a distinct reddish tinge. They called this rose coloured gold alloy umbago.

Tumbaga is a gold and copper alloy. The melting point of this alloy is considerably lower than gold or copper on their own. Tumbago is harder than copper. Tumbage also maintains malleability after it has been worked.

When tumbaga is treated with acid (citric acid for instance) the surface copper is dissolved leaving a layer of almost pure gold which is as shiny as pure gold. This shiny layer lays atop the harder, more durable copper-gold alloy beneath. It was a sight to behold for the gold thirsty Spanish conquistadors. It was irresistible..

This process is known today as depletion gilding. Probably not a term the Meso-American's used.

Rose Gold Alloy Used in Jewellery

The quality of pink to rose colouring of highlights and tones depends upon the quantity of copper which is used in the formula.

These gold and copper alloys are widely used for specialized jewellery. This reddish tint works well with certain fair skin tones, and it has a unique quality that stands apart from its more commonly used yellow counterpart. They accentuate the gold with a pinkish blush.

The combination of gold and copper gives rose gold both strength and beauty, making it the standard for fine watches and vintage jewellery. Rose gold jewellery has a subtle richness that is best shown off with elegant, timeless designs.

Yellow gold and rose gold normally have approximately the same price.

Rose Gold was popular in Russia at the beginning of the nineteenth century. For this reason rose gold has known as Russian gold.

To read the covering article in this series see Gold :: Rose Gold, Red Gold and Pink Gold by Humagaia.

To read the next article in this series see Gold :: White Gold by Humagaia

To read the previous article in this series see Gold :: Red Gold by Humagaia