Colors taken on by gold and its alloys depending on their composition

If you are looking for gold jewelry and want to learn more about this precious metal, you may feel a little lost among all the colors gold jewelry can take on.

In fact, depending on the composition of the alloy, gold can be white, pink, green or even black if we consider modern surface treatments. There are a total of 9 different shades given to gold depending on its composition or the surface treatment received.

Panel of the colors assumed by gold depending on the composition of the gold alloy.

To help you see more clearly, this article presents all the colors that gold alloys can take on depending on their composition:

Color of the gold alloys most commonly used in jewelry

As you may know, gold is a very malleable metal in its pure state, so for fine gold jewelry designs it is essential to «harden» it by alloying it with other metals. The silver and copper used for these purposes can change the color of gold depending on their proportions in the alloy, this feature has long been used in goldsmithing.

The table below shows the shades obtained by combining different proportions of copper and silver with gold.

Nowadays the «recipes» for coloring gold are more elaborate and also use other metals (Palladium, Zinc, Platinum, etc.). While most jewelers use commercially prepared alloys, some jewelry stores and major brands also have their own recipes for making their own gold coloring, a hue whose composition is kept secret. The information reported here is therefore indicative.

In addition to changing the color of gold, the metal alloy also facilitates the processing of gold by rolling, casting or polishing. It can also improve frictional wear resistance. Gold alloys that are innovative in color or mechanical properties are therefore protected by patent filings.

Yellow gold: hardens without altering its color

Although gold is naturally yellow in color, to ensure that it maintains its color by adding copper and silver a good dosage of each metal is necessary, because it is also necessary to respect the legal fineness of the gold. This topic has been covered in this article on gold karats.

Composition of 22 carat yellow gold (917/1000): 91.7% Fine Gold + 5% Silver + 2% Copper + 1.3% Zinc

Composition of 18k yellow gold (750/1000): 75% fine gold + 12.5% ​​copper + 12.5% ​​silver

Composition of 14 carat yellow gold (583/1000): 58.3% fine gold + 11.5 to 25% silver + 11.5% to 23% copper + 2 to 7% zinc

Composition of 9 carat yellow gold (375/1000): 37.5% Fine Gold + 12.1% Silver + 44.4% Copper + 6% Zinc

View of two 14k yellow gold chains whose shade of yellow varies due to the composition of the alloy.

White gold and white gold have the same basis:

White gold used in jewelry is very often covered with a layer of rhodium to give it the final color. In fact, most white gold alloys are so called because they include metals that whiten the gold, however, the final shade in most gold tends to be light gray.

Only the use of metals such as Palladium (very expensive), Nickel (banned in France since 2000 because it is allergenic) and Cadmium allows mass-coloured white gold to be obtained.

Or White

Composition of 20 carat white gold (833/1000): 83.3% Fine Gold + 16.7%% Palladium

Composition of 18k white gold (750/1000): 75% Fine Gold + 18.5% Silver + 1% Copper + 5.5% Zinc

Composition of 14 carat white gold (583/1000): 58.3% Fine Gold + 17% Silver + 17% Copper + 7.7% Zinc

Composition of 9 carat white gold (375/1000): 37.5% Fine Gold + 62.5% Silver

Or Gris

Composition of 18k gray gold (750/1000): 75% Fine gold + 17% Iron + 8% Copper

Custom made white gold ring with rhodium plating

The shade from rose gold to red gold mainly depends on copper

It is the copper that gives rose gold its more or less red color depending on its content in the alloy. Rose gold was very popular among Russians at the beginning of the 20th century, hence its name: Russian gold.

Or 18 carats

Composition of 18k red gold (750/1000): 75% fine gold + 25% copper

Composition in 18k rose gold (750/1000): 75% Fine Gold + 22.25% Copper + 2.75% Silver

Composition of 18k rose gold (750/1000): 75% fine gold + 20% copper + 5% silver

Or 14 carats

Composition of 14 carat red gold (583/1000): 58.3% Fine Gold + 32.5% Copper + 9.2% Silver

Composition in 14k rose gold (583/1000): 58.3% Fine Gold + 24.5% Copper + 17.2% Silver

Or 9 carats

Composition of 9 carat red gold (375/1000): 37.5% Fine gold + 55% Copper + 7.5% Silver

Composition of 9 carat rose gold (375/1000): 37.5% fine gold + 42.5% copper + 20% silver

Rose gold shades depending on the copper content of the gold

Green gold also known by the ancient term electrum

Green gold is actually a natural alloy of gold and silver called Electrum. Its reflections range from yellow with light green reflections to more pronounced green.

Composition of 14 carat green gold (583/1000): 58.3% fine gold + 32.5% silver + 9% copper + 0.2% zinc

The exotic colors of gold

Black gold

Although quite rare in jewelry, black gold is still the most used of the exotic colored golds. It can be obtained by surface treatment of white gold or by alloying cobalt with gold and then by heat treatment.

To find out more, I invite you to read this article which specifically deals with black gold.

18k black gold composition: 750/1000 white gold + black rhodium surface treatment

Men’s black gold wedding ring

Blue gold

Composition of 18k blue gold (750/1000): 75% fine gold + 24.4% iron + 0.6% nickel. The alloy is then heat treated to oxidize the iron and thus obtain a blue surface color.

Please note that although nickel jewelry is prohibited, there are permissible emission standards. Consult the decree of 18 July 2000 relating to the ban on nickel to find out more.

For more information on blue gold I invite you to consult the patent that concerns it directly here.

Another composition, that of 11 carat blue gold (460/1000): 46% fine gold + 54% indium

The Swiss jeweler Ludwig Muller specializes in working with blue gold.

Purple gold

Purple gold is fragile and is therefore mainly used as an inlay on more conventional gold jewelry.

Composition of 19k purple gold (800/1000): 79% fine gold + 21% aluminum

Yellow gold ring with purple gold inlay (photo source)

Sources:

Article to read to learn more about exotic gold alloys

Interesting article on natural alluvial gold alloys of surprising composition and colour.

To go further: