Gold

Gold is one of the most precious metals in the world. Undoubtedly, it is the oldest precious metal in the history of mankind. Due to its wonderful qualities and its magnificent luster, gold is considered the most important metal in jewelry making.

The purity of gold is measured in terms of Karats or in terms of fineness (i.e., European Marking). Pure gold is 24 Karats or 1000 fineness. Gold is usually a mixture of various metals which is called an alloy. A karat is the percent of pure gold in the alloy. Therefore, one can determine the percentage of pure gold in any gold piece by dividing the karat by 24 (e.g., 18K gold: 18/24=0.750=75% pure gold).

Gold is a precious metal. Through a combination of its relative scarcity and its noticeable beauty, gold became a very valuable product throughout the history of mankind. Apparently, gold is the oldest metal considered precious to human beings. Throughout human history, gold has been the cause for wars, in which many people have died while trying to gain it or protect it.

As an element, gold is a metal, with the atomic number 79 in the Periodic Table of the Elements. Its physical and chemical properties make it ideal for a number of applications. It is a very stable element, which means that it seldom combines with other elements. In other words, gold does not corrode or rust. In addition, gold is a good conductor of electricity and heat. Gold is also very malleable which means it can be shaped with relative ease. In fact, gold is malleable to such an extent that it can be hammered into a sheet so thin that light can pass through it. Gold is also ductile, that is to say, it can be drawn into long, thin wires, for example, a wire thread approximately 50 miles long can be drawn from a single troy ounce of gold (31.1 grams). Gold is also a very dense metal; a cubic foot of gold weighs over 1,200 pounds.

In the Periodic Table of the Elements, the chemical symbol of gold is Au. The symbol Au comes from the Latin word aurum, which means "shining dawn." Apparently, this is a direct reference to the bright yellow color of gold and its shiny luster. The origin of the English word gold is in Middle English.

Gold can be mined in two primary types of deposits. The first type is called Lode deposits or Vein deposits. Lode deposits are deposits where gold is found in cracks and veins in rocks. The second type of gold deposits is called Placer deposits. Placer deposits are formed by moving water that has eroded gold out of lode deposits. When the velocity of the water in a river slows sufficiently, the heavy gold falls to the bottom and accumulates in the sand of the riverbed. Gold is also available as a by-product of copper and silver mining. Because gold is very valuable, it is profitable to recover even small amounts from copper and silver ore.

Some experts estimate that there are at least 100,000 tons of gold yet to be mined on planet Earth. The largest producer of gold in the world is South Africa, which has at least half of all the gold resources on Earth. Other leading countries with significant deposits of gold are the United States and Brazil.

Approximately one-fifth of the total resources of gold in the world are the by-product from copper and silver ores.

In the United States, Alaska and Nevada are the chief producers of gold. A considerable amount of all the gold produced in the United States is produced in Nevada. The rest of the gold comes from placer deposits in Alaska and other gold deposits in several western states. Only 30 mines throughout the United States recover the majority of the gold in the United States. Nowadays, the largest gold mines in the United States are located in Northern Nevada. Nonetheless, the United States imports a significant amount of gold from Brazil and Canada.

In the past, gold was a rare metal that only the wealthy could afford. During the 19th Century, however, a new route of gold supply was uncovered in California and Australia. In addition, machinery for producing jewelries and other fashion articles was developed and perfected. As a result, the consumer market for gold rapidly expanded. Nowadays, in many industrial countries, gold is a fashion item in great demand.

Gold does not tarnish or corrode. Although it is a very strong metal, gold is the most malleable. Therefore, gold is frequently mixed or alloyed with other metals in order to make the gold harder. However, mixing gold with other metals also affects the color. For instance, gold must be alloyed with silver, nickel or palladium in order to get white shades of gold (e.g., white gold).

The Karat Scale is used for measuring the proportion of gold in jewelry. Accordingly, 24 karats denotes pure gold, 12 karat gold is 50% gold and 50% alloy, and so forth.
The Karat Scale:

In the United States, 14 karat and 18 karat are the most popular forms of gold jewelry. The 18 karat is popular because it is rich in color and it is durable.

Gold alloys, besides making gold hard enough for manufacturing jewelry, can also affect the color of gold. The following list includes the most common colors of gold alloys and the metals used for producing them: