In a previous blog post we talked about how adjusting the karat level of gold can affect the qualities in a piece of jewelry. Of course, pure gold is a constant in the science of crafting gold jewelry. But, there are many variations when deciding on which metals to alloy with the gold to lower the karat level. And while all metals will lower the karat level, they don’t all create jewelry that has the same qualities.
Color is the most obvious of these qualities. When gold is alloyed with another metal, its hue changes. For example, white gold is a very popular alloy in jewelry making. It can be created by mixing gold with a white metal – usually nickel or palladium. Depending on the white metal used, the piece of jewelry can take on different properties. Nickel is inexpensive and does a great job of increasing the wear-resistance of the jewelry. However, it will still look a bit yellow and require a rhodium plating to improve the shine and white color. On the other hand, white gold made with palladium will have a much better natural luster and color, but will still be quite soft.
Of course, there are even more gold alloys – all with different colors and physical properties. Rose gold is made with copper; green gold (aka electrum) is made with silver; grey gold is made with silver, manganese, and copper; and the list goes on.
On top of using a range of gold alloys, jewelry can also be made with gold in different ways. To make gold plated jewelry, a base metal (such as steel or brass) is electroplated with a very thin layer of gold. This yields jewelry that is very inexpensive and lustrous, but easily worn out. Gold filled jewelry (aka, rolled gold) is made the same way, but uses a much thicker layer of gold – at least five-percent of the jewelry’s total weight. Vermeil is a form of the gold plating process, but is reserved for more elegant pieces. To create vermeil, sterling silver is used as the base metal and the gold plating is usually 22-24kt.
For our next entry in this series, we’ll explore how the other precious metals are refined to accommodate jewelry designs.