What is Gold?

Symbol: Au

Atomic Number: 79

Melting Point: 

1337 °K, 1948 °F, 1064 °C

Boiling Point:

3129 °K, 5173 °F, 2856 °C

Uses:

Gold is the most malleable and ductile of all metals. A single troy ounce of gold can be beaten into a flat sheet measuring roughly 5 meters on a side. Thin sheets of gold, known as gold leaf, can be as thin as 0.000127 millimeters, or about 400 times thinner than a human hair.

Pure gold is soft and is usually alloyed with other metals, such as silver, copper, platinum or palladium, to increase its strength. Gold alloys are used to make jewelry, decorative items, dental fillings and coins. Gold is a good conductor of heat and electricity and does not tarnish when it is exposed to the air, so it can be used to make electrical connectors and printed circuit boards. Gold is also a good reflector of infrared radiation and can be used to help shield spacecraft and skyscrapers from the sun's heat. Gold coated mirrors can be used to make telescopes that are sensitive to infrared light.

 

Measurements

Commonly used measurements often used when dealing with gold are carat and troy ounce.

The amount of gold in an alloy is measured with a unit called a carat.

One carat is equal to one part in twenty-four, so an 18 carat gold ring contains 18 parts pure gold and 6 parts alloy material.

Precious metals like gold are measured in troy ounces and troy pounds. The troy ounce is approximately 10% heavier than a typical grocery store (avoirdupois) ounce. A troy pound weighs approximately 17% less than a grocery store pound.

20 pennyweights = 1 troy ounce = 31.10 grams

12 troy ounces = 1 troy pound = 373.2 grams

History:

An attractive and highly valued metal, gold has been known for at least 5500 years. Gold is sometimes found free in nature but it is usually found in conjunction with silver, quartz, calcite, lead, tellurium, zinc or copper.

It occurs in either veins or alluvial deposits and is recovered by hard rock or placer mining. The gold deposits of the Klondike region were placer deposits. This meant the gold could easily be extracted by panning or sluicing and didn't require the need for heavy earth moving equipment or blasting.

It has been estimated that all of the gold that has currently been refined could be placed in a cube measuring 20 meters on a side.

From National Park Service

http://www.nps.gov/klse/naturescience/what-is-gold.htm

The ten biggest gold mines in the world

Here is a list of the 10 biggest gold mines in the world, based on available 2010 production data:

1. Grasberg Gold Mine -- This mine, which is in the Indonesian province of Papua, produced 2,025,000 ounces of gold, according to the annual report of Rio Tinto Plc. The mine is majority owned by Freeport-McMoRan Copper & Gold Inc. Besides gold, it also produces silver and copper.

2. Muruntau Gold Mine -- This mine, which is about 250 miles west of the capital in Uzbekistan, is believed to have produced approximately 1,800,000 ounces of gold last year. The project, which is an open-pit operation, is run by state-owned Navoi Mining and Metallurgical Combinat.

3. Carlin-Nevada Complex -- This mine, which is in the U.S. state of Nevada, produced 1.735 million ounces in 2010. It is owned by Newmont Mining Corp. It includes both open-pit and underground operations.

4. Yanacocha Gold Mine -- This mine, which is in northern Peru and is the largest gold mine in Latin America, produced 1.46 million ounces last year. It is run by Newmont Mining and owned by Newmont Mining and Buenaventurda, a Peruvian company.

5. Goldstrike (Betze Post) Gold Mine -- This mine, which is northwest of Elko, Nev., produced 1.24 million ounces of gold last year. It is owned by Barrick Gold Corp.

6. Cortez Gold Mine -- This mine, which is southwest of Elko, Nev., produced 1.14 million ounces of gold last year. It is owned by Barrick Gold.

7. Veladero Gold Mine -- This mine, which is in Argentina, produced 1.12 million ounces of gold last year. It is owned by Barrick Gold.

8. Lagunas Norte Gold Mine -- This mine, which is in north-central Peru, produced 808,000 ounces of gold last year. It is owned by Barrick Gold. 

9. Lihir Gold Mine -- This mine, which is in Papua New Guinea, produced 790,974 ounces of gold in the 12 months ended June 30. It is owned by Newcrest Mining Ltd., Australia's largest gold producer.

10. Super Pit/Kalgoorlie -- This mine, an open-cut mine in Western Australia, produced 788,000 ounces last year. It is 50-50 owned by Barrick Gold and Newmont Mining. 

From International Business Times

http://www.ibtimes.com/10-biggest-gold-mines-world-photos-553223