Gold is a chemical element that, aside from its extraordinary luster, has amazing physical characteristics that make it extremely well suited for use in jewelry making. Although it is the most malleable (able to be shaped into many forms) of all metals, gold is so durable that it is virtually indestructible. One ounce (28 g) of gold can be hammered to 187 square feet, in extremely thin sheets called gold leaf. Gold also does not tarnish or corrode. Gold can be re-melted and used again to create new designs.
Because pure gold is too soft to resist prolonged handling, it is usually mixed with other metals to increase its hardness for use in jewelry. Most gold used in jewelry is alloyed with silver, copper and small amounts of zinc to produce various shades of yellow gold, or with nickel, copper and zinc to produce white gold. The color of these gold alloys goes from yellow to white as the proportion of nickel in them increases. Alloys with platinum or palladium are also used in jewelry. Alloying gold with copper creates what is known as pink gold. Since nickel is the most popular alloy used in white gold, it is important to note that some people may be allergic to nickel. People with this sensitivity can avoid problems by choosing 18-Karat gold, instead of 14-Karat (since there is more pure gold and less alloys in 18K), or by choosing platinum settings.
The gold content of a piece of jewelry is measured in karats, which can range from 1 to 24. For example, 14 Karat (14k) gold is 14 parts of gold to 10 parts other metals. The higher the karat of a piece of jewelry, the greater its gold content. This term should not be confused with the term carat, which is measure of the weight of diamonds and other gemstones.
Gold pricing is based on a number of factors, including karat amount (called karatage), gram weight, design and craftsmanship. The karatage and gram weight designate how much gold is in a piece, but are not the sole determining price factors. The craftsmanship and level of detail in a piece are also taken into account. Other important considerations are the piece's construction and design. Higher quality pieces that are well made will last longer, and are usually priced higher.
The most critical thing to look for in buying gold jewelry is the purity of the gold. The higher the gold content, the more valuable it is. The amount of gold in a piece is represented in the karat mark, usually inscribed on the back of the piece (e.g. 24K, 18K,14K, etc.). The European system uses numbers representing a fraction of 1000, so “750” would be 75% gold, or the equivalent of 18 Karat. In addition to the karat mark, every piece of gold jewelry should be stamped with a hallmark or trademark of its manufacturer and sometimes its country of origin. In the United States, 14-karat gold, or 585 parts pure gold, is the most common degree of fineness and pieces are marked 14K. Nothing less than 10K can legally be marked or sold as gold jewelry in the U.S.
Gold filled jewelry is made by joining or bonding (under heat and pressure) layers of a karat gold to a base metal. This 'sandwich' is then rolled or drawn to the desired thickness. Gold-plated jewelry is made by bonding 10-karat or better gold to a base metal. The karat gold content may be less than 1/20, but must be properly identified as a percentage of the total content.The history of gold extends back at least 6,000 years, with references to it being made in both Egypt and Mesopotamia. In ancient times, gold was thought to have healing properties when worn or even ingested. It is even mentioned several times in the Old Testament.
From Christopher Columbus' discovery of the New World in 1492 to 1600, more than 8,000,000 ounces of gold, or 35 percent of world production, came from South America. The New World's mines--especially those in Colombia--continued into the 17th and 18th centuries to account for 61 and 80 percent, respectively, of world production. 48,000,000 ounces were mined in the 18th century.
Russia became the world's leading producer of gold in 1823, and for 14 years it contributed the bulk of the world supply. From 1850 to 1875, more gold was produced in the world than in all the years since 1492, primarily because of discoveries in California and Australia. A third increase in gold production stemmed from discoveries in Alaska, Yukon Territory and South Africa. Gold production continued to rise throughout the 20th century, partly because of the improvement in recovery methods and partly because of the continual growth and expansion of South Africa's gold-mining operations.
In the late 20th century, South Africa, Russia, the United States and Australia accounted for two-thirds of the gold produced annually throughout the world. South Africa alone produces about one-third of the world's gold. Today gold is also used in the medical industry, because its infrared detection capabilities make it ideal for being traced throughout the body. And of course, dentists use 13 tons of gold every year inside our mouths!