Buying Gold and Gemstone Jewelry: The Heart of the Matter

If you're planning a gift of gold or gemstone jewelry for your sweetheart, take some time to learn the terms used in the industry. Start with the basics. Carats and karats. What's the difference? Simply put, a carat is a unit of weight for gemstones, including diamonds; a karat is a unit for measuring the purity of gold.

Gold





The higher the karat rating, the higher the proportion of gold in the piece of jewelry. For example, 24 karat (24K) gold has more gold content than 14K gold. But because 24K gold is soft, it's usually mixed with other metals to increase its hardness and durability; 14K jewelry contains 14 parts of gold, mixed in throughout with 10 parts of base metal.

There's a big difference between karat-gold and gold-plated jewelry. Gold-plated describes jewelry with a layer of at least 10K gold bonded to a base metal. Gold plating eventually wears away, depending on how often the item is worn and how thick the plating is.

Gemstones


Gemstones can be naturally mined, laboratory-created or imitation. Stones created in a lab look identical to stones mined from the earth. The big difference is in the cost - laboratory-created stones are less expensive than naturally mined stones. But because they look just like stones mined from the earth, they must be identified as lab-created. Imitation stones resemble naturally mined stones but are not identical and are usually made of glass or plastic. Imitation stones must be identified as imitation. If you are purchasing a naturally mined stone, ask if it has been treated. Gemstone treatments - such as heating, dyeing or bleaching - can improve a stone's appearance or durability. Some treatments are permanent; some may create special care requirements. Treatments also may affect the stone's value.

Gold is Gold

Gold is a soft, very dense metal which is highly valued for use in jewelry and coinage. Called a "noble metal", it does not react readily in ordinary chemical reactions, so it can be found in essentially pure form as gold nuggets. It is also used in dental work because it can be precisely shaped and does not react chemically in the mouth. Its high electrical conductivity makes it valuable for tiny electrical contacts, and its very high reflectivity has led to use in thin films as a reflector.

Gold is bright yellow by reflected light, but in thin films may be blue or green.

Gold is the most malleable and the most ductile of all metals. It can be hammered into sheets only 1/100,000 cm thick and drawn into wires 1/5000 cm in diameter.

Gold is often alloyed with copper, silver, palladium or other metals. The amount of gold in these alloys is described in carats. The carat value is the number of parts of gold in 24 parts of alloy, so that 24 carat gold is the pure metal. American coinage gold is 21.6 carat and British coinage is 22 carat.

White gold as used in jewelry is usually an alloy of gold and nickel.

Gold is found in the mineral nagyagite, a sulfide, along with lead, iron, antimony, and tellurium. Tellurium combines with gold to form krennerite, AuTe2.