Gold Color and Purity
To make jewelry more suitable for everyday wear, pure gold is almost always alloyed with other metals principally copper and silver. By altering the proportions of these additive ingredients, several colors can be made.
What is Karat?
When speaking about gold, both karat and carat refer to the purity of the gold. This is not to be confused with carat weight which is a unit of measure of a gemstone’s mass.
What does it mean when people speak of 14 karat, 18 karat, 19 karat, and 24 karat gold? What’s the difference between these designations and 585 gold, 750 gold or 950 platinum for that matter? They are just different ways of expressing the purity of gold or precious metal content in jewelry.
How Is Gold Karat Calculated?
24k is the numeric designation for pure gold. The most common gold alloys used in North American jewelry are 18K and 14K. The caratage or purity of gold is calculated as follows:
24 karat (pure gold) 24k / 24k = 1.000 1.000 x 100 = 100 % pure
19 karat (792 gold) 19k / 24k = 0.791 0.791 x 100 = 79.1 % pure
18 karat (750 gold) 18k / 24k = 0.750 0.750 x 100 = 75.0 % pure
14 karat (585 gold) 14k / 24k = 0.583 0.583 x 100 = 58.3 % pure