Yellow gold
Yellow gold is the most common gold used in jewelry making. It is necessary to know that although yellow gold is the same color as gold metal, but their purity is not equal. Pure gold that exists in nature is very soft and is not a suitable option for jewelry making. For this reason, it is alloyed with other metals to increase the hardness of the product. The higher the gold grade, the less hard it is, but the more pure it is. It means that the golds that are of low quality are hard and stable, but the purity of their gold is less.
White gold
The most common alloy used in jewelry is white gold. To achieve this color, gold metal is alloyed with metals such as palladium or nickel. Of course, this composition still has a shade of yellow in it. In order to make the gold completely white and shiny, a layer of rhodium is applied on it. Since some people are allergic to nickel, instead of nickel, palladium (from the group of platinum metals) is used. Platinum is more expensive than nickel but is less likely to cause allergic reactions. If palladium is used in white gold, there is no need for rhodium plating because palladium gives the gold a gray color. Usually, when the rhodium coating is worn, the gold is seen a dull yellow color.
White gold is sometimes made from the combination of gold with nickel, copper and zinc. These metals give white color to gold. The price of white gold is not different from yellow gold and you can buy it both in gold shops and online.
Rose Gold
They use copper metal to make rose gold. They alloy gold and copper and create this pink color. The more copper, the more rose gold it will be. This gold is also known as "red gold". Of course, if less copper is used in its composition, the color of the alloy will be pink, which is also known as "pink gold". Rose gold is more modern than today's yellow and white gold, and you can buy it in jewelry stores. Its price is no different from yellow and white gold.
Black gold
Black gold is gold that has a layer of ruthenium coating on it to make it stronger. Of course, gold metal can be darkened in various ways. One of the most common methods is the use of black rhodium plating. Another way is to blacken the alloy under various chemical reactions. The color of other metals such as cobalt, copper, titanium or iron can also be blackened by heating and oxidizing. Another way to make black gold is to oxidize the metal and then add a rust or patina to the metal.
Green gold
This gold is obtained from the combination of silver and gold. There is no copper in the composition of this type of gold. Green gold is more unusual than other colors of gold and is often used to complement designs that have been used in gold. In some (very limited) cases, they also use cadium. The green color of the gold alloy is not very intense and has more of a shade of green. Nowadays, many people use green gold for wedding rings. Since silver darkens over time, green gold that has silver in it will darken slightly over time.
Gray gold
This color of gold is the result of the combination of gold and palladium. They increase or decrease the amount of palladium to make the desired birch color. But this combination costs a lot. For this reason, silver, manganese and copper compounds should be used instead of palladium to make this combination affordable.