To estimate the value of the setting’s metal, find out its exact weight, and then look up the current market price for that particular metal. If you don’t know the exact metal type, look inside the ring band for a stamp describing the setting’s metal. A stamp such as “10K,” “14K,” “18K,” “585,” “750,” “PT900,” and ”PT950,” describe the metal used.
Gold purity is measured in karats and refers to the amount of pure gold present in the jewellery. Twenty-four-karat gold is considered to be pure gold, or 99.9% pure to be exact. Dividing the karat unit by 24 will provide the percent of pure gold in the jewellery. Thus, if you are wondering how much gold is in the 18-karat wedding band you are wearing, divide 18 by 24 to get 75%. Your wedding band gold is 75% pure.
Below is a breakdown of the percentage of pure gold in each of the popular karat weights:
Yellow gold in its pure form is rarely used to produce jewellery. Most 24-karat gold is sold as investments to world governments and central banks as well as private investors. Twenty-four-karat gold is too soft and not durable enough to use for jewellery. Jewellers use different alloys, combining gold with other metals to give it more hardness. For example, the most popular grade of gold purity is 18-karat, meaning three-quarters of the alloy is gold and one-quarter is a mixture of copper and silver.
White gold combines pure gold with other white metals, such as zinc, nickel, platinum and silver. Durable and resistant to tarnish, white gold jewellery is brittle and requires rhodium plating. Generally produced to be a more cost effective than platinum, white gold can cause allergic reactions once the plating wears off.
Rose gold is an alloy that combines gold with copper to create a golden metal with a reddish hue. While it normally uses a gold to copper ratio of 3:1, rose gold can be found with varying percentages of each. Based on the addition of copper, the intensity of rose gold will be lighter or darker and will patina over time.
Platinum is a silvery, white metal that's extremely rare and considered more precious than gold. Priced significantly above gold, platinum is among the heavier metals used in jewellery. Despite this increase in cost, platinum jewellery has become increasingly popular especially in platinum engagement rings and wedding rings. Platinum is commonly mixed with iridium. However, for a piece of jewellery to be labeled as "platinum" it must have a minimum level of purity of at least 95% pure platinum.