Gold

Gold has been one of mankind's most revered substances since the beginning of time. Throughout history, great civilizations have built up treasuries of this precious metal, reserving golden objects for their most important rituals and ascribing miraculous powers to it.

The ancient Egyptians equated gold with the sun, the giver of life, and reserved its use for pharaohs only. The Etruscans created meticulously handwrought objects using fine granules and threads of gold, a technique still practiced today. The Chinese saw gold as the yang of the sun (with silver representing the moon's ying). To this day, Chinese and Indian brides wear jewelry of no less than 24-karat gold on their wedding day to ensure a lifetime of good luck and happiness. Meanwhile, the Incas called gold the "sweat of the sun."

In some cultures, gold is even eaten to cure such ailments as arthritis, ulcers and tuberculosis.

But perhaps the most alluring use of the sun-colored metal has always been in jewelry. In fact, three-quarters of the world's gold mined each year is used to make jewelry. The metal's permanence has made it a symbol of enduring love and heritage, and pieces are passed down from generation to generation. It is the recommending jewelry gift for couples celebrating their 50th wedding anniversary.

The factors that have driven gold's everlasting, universal appeal are numerous:

• Gold is extremely rare - It is estimated that all the gold ever mined would fit underneath the Eiffel Tower in Paris. It takes several tones of ore to produce just one ounce of gold.
• Gold is beautiful - Jewelers throughout history have preferred gold to all other metals for its warm golden color. The metal also takes well to alloying with other metals, which has allowed metalsmiths to create a rainbow of shades for gold. For instance, mixing gold with copper creates rose gold; mixing gold with silver creates green gold; and mixing it with palladium produces white gold.
• Gold is durable - The sheer amount of gold jewelry, coins and artifacts from ancient cultures on display in the world's museums is a testament to the metal's enduring beauty. It is extremely heavy, with one cubic foot weighing half a ton. Although pure gold is relatively soft, it becomes exceptionally strong when alloyed with other metals. Because of its indestructibility, gold is used by the electronics industry to create 10 billion tiny electrical contacts each year.
• Gold is pure - Because of this purity, it is not affected by air, heat or moisture and is resistant to tarnish. These properties have helped make gold bullion such a valuable commodity.
• Gold is extremely malleable - Gold is so easy to work with that a single ounce can be drawn out into an unbroken strand approximately 60 miles long. It can be melted or shaped to create any design.

Here are some common gold karatages (karat weights) and the corresponding percentages of actual gold:

• 24K represents pure gold (100%) and is rarely used in jewelry.
• 21K is 21/24ths gold content, or 87.5% gold. Jewelry of this karatage or higher is rare in the United States, although it is far more common in parts of Europe, the Middle East and Southeast Asia.
• 18K is 18/24ths gold content, or 75% gold. This is a popular karatage for higher end jewelry in the United States, Europe and other regions, and its usage is expanding in North America.
• 14K is 14/24ths gold content, or roughly 58.5% gold. This is by far the most commonly used karatage in the United States (and perhaps the world) and provides a nice balance between gold content, hardness/durability and affordability.
• 10K is 10/24ths gold content, or 41.7% gold. This is an increasingly popular karatage sold by many U.S. mall jewelry chains, department stores, discount stores and other mass market venues because it offers budget-conscious consumers precious metal jewelry at more affordable prices than the standard 14K. It is also the lowest gold content that can be legally marked or sold as gold jewelry in the United States. Often used in rings because they tend to be worn every day and experience many knocks and thus require an exceptionally strong alloy.
• 9K is 9/24ths gold content, or 37.5% gold. This is a popular karatage sold by mass marketers in England and other regions, although it cannot be marked or sold as gold jewelry in the United States.

The tint the gold takes on depends on the metals it is mixed, or alloyed with. Here are the main shades of gold:

• Yellow gold - This is gold in its natural shade. It is by far the most common type of gold used in jewelry. Yellow gold used for jewelry is usually alloyed with copper and silver to strengthen it. The warm glow of yellow gold works with virtually any outfit, any skin or body type and any gemstone. How yellow a piece is will depend on its gold content. Generally, 14 karat gold has a brighter yellow than 10 karat gold; 18 karat gold has a deeper yellow than 14 karat gold, and so on.
• White gold - White gold has become very fashionable in recent years as many consumers have opted for the cool, contemporary white look over the classic yellow look. White gold has the same properties as yellow gold, but is mixed with different alloys to give it its white color. Generally, white gold is created by using a nickel or palladium alloy, zinc and copper. Sometimes, white gold is plated with an even whiter metal, such as rhodium (a rare member of the platinum family) to enhance its appearance. A white gold setting can enhance the look of white diamonds and put a modern twist on a traditional standard.
• Rose gold - By alloying just copper with yellow gold, metalsmiths can create gold with a pink, blush-like tint, which experts say lends a soft, flattering effect to the skin.
• Green gold - This alloy is created by mixing silver, copper and zinc to yellow gold.

The other types of gold jewelry include gold-filled, gold-plated and vermeil. Gold-filled refers to a layer of gold mechanically bonded to a base (non-precious) metal; the gold content must be at least 1/20th of the total weight of the piece. Gold-plated merchandise has a coating of 10 karat gold or higher applied to a base metal by electrolysis. Vermeil is jewelry that is made by applying a layer of karat gold to a sterling silver base

To determine the karat weight of a particular piece of jewelry, look for the quality mark. Generally, pieces will either bear the stamp of their karatage based on the U.S. or European system. The U.S. system uses karat designations (24K, 18K, 14K, 10K, etc.) Europe uses number designations which correspond to the percentage of gold content. For instance, 10K is marked "417" for 41.7% gold; 14K is marked "585" for 58.5% gold; 18K is marked "750" for 75% gold, etc