Gold’s purity is measured in "karats". 24 Karat gold is pure gold, but its purity means it is more expensive and less durable than gold that is alloyed with other metals.
(parts of gold per 24) (parts of gold per 100)
24 Karat 100 percent
18 Karat 75.0 percent
14 Karat 58.3 percent
10 Karat 41.6 percent
The weight of gold or gold articles is usually expressed in troy ounces and/or pennyweight (dwt)
1 Troy ounce = 1.097 ordinary ounce
1 Troy ounce = 20 pennyweight (dwt)
The "d" in the traditional symbol for pennyweight (dwt) is from the Latin denarius, the small Roman coin which was the equivalent of a penny.
Yellow Gold is alloyed with silver and copper. It is the most frequently used type of gold there is.
White Gold is alloyed with a large percentage of silver and is therefore more expensive than yellow gold. White gold is highly reflective and not subject to tarnish.
Rose Gold is alloyed with copper and silver.
Ex: 14kt yellow gold is 58.3% gold, 30% silver & 11.5% copper
14kt rose gold is 58.3% gold, 9% silver & 32.5% copper
By U.S. law, every gold article must have a karat mark. In addition to the karat mark, every piece of gold jewelry should be stamped with a hallmark or trademark of the manufacturer.
Gold Regional Preferences
Each part of the globe has very different expectations of what "gold" is.
United States 14karat/10karat
European Union 18karat/14karat
10 karat gold in the U.S. is very common and an acceptable alloy. Other parts of the world do not recognize or accept jewelry marked 10K as precious.
Gold-Plated versus Gold Filled
Gold-plated jewelry has a thin layer of gold that has been applied to any base metal item by means of an electroplating (or dipping) process.
Gold-filled refers to stock material which is made by combining a layer of gold to a layer of base metal. The thickness of the gold layer will determine the percentage of gold by weight. It may be 5%, 10%, 15% or 20% gold.
Fine silver in its natural state, 999/1000 pure, is almost as soft as gold, too soft an element for practical jewelry. To make it workable, an alloy such as copper is added. The following are the more common silver alloys:
Sterling Silver - A mixture of 92.5% silver and 7.5% metal alloy Sometimes jewelry made of this metal mixture is marked .925, to indicate that the
metal is at least 92.5% pure silver
Mexican Silver - 90% - 99% pure silver
Coin Silver - 90% pure silver and 10% metal alloy
German Silver or Nickel Silver - A silver white alloy consisting of copper, zinc, and nickel
Vermeil - Sterling Silver electroplated with karat gold