Gold, a transition element is the third element in the 11th column of periodic table. It has an atomic number of 79 and its symbol is Au. The Latin world for gold is ‘Aurum’, which explains the symbol. It has a melting point of 1064°C and a boiling point of 2856°C. Since ancient times, gold is much sought after for use in coinage, jewelry and other arts.
Just like other members of its group, gold is also very ductile and a good conductor of electricity and heat. It strongly reflects infrared radiations. In its purest form, gold has a reddish yellow color. It is one of only four metals that are not silver or grey in color.
Another characteristic of gold is its high degree of malleability. Gold is not very reactive and is fairly resistant to corrosion. It is largely insoluble and only solutions of nitro-hydrochloric acid, sodium and potassium cyanide have the ability to dissolve gold. In fact this ability to dissolve the king of metals, earned nitro-hydrochloric acid the name, ‘aqua regia’ or royal water. Gold is also very dense and a cubic meter of gold could weigh up to 19,300 kilograms.
Gold is primarily used for manufacturing jewelry. According to estimates 50 percent of world’s new gold is used in jewelry making, 40 percent in investment and 10 percent in industry. Gold in its purest form is very soft and is therefore, alloyed with other base metals like copper, silver and palladium. Gold is widely used for manufacture of corrosion free electrical connectors in computers and electrical devices. It is also used in medicine industry and in restorative dentistry. Certain gold salts are known to possess anti-inflammatory qualities and are used in drugs for pain and swelling management in case of rheumatoid arthritis.
Listed below are some very interesting and rarely known facts about gold:
- Gold is one of the most malleable metals in the world. Such is the extent of its malleability that it can be hammered into a thin sheet which is almost transparent.
- The entire gold of earth came from the meteorites that rained upon earth almost 200 million years ago.
- Gold and mercury readily form an amalgam, even at room temperature.
- Iron Pyrite, a mineral is very similar to gold in appearance and is therefore called ‘fool’s gold.
- 24K is the purest form of gold. Gold’s amount in various alloys is measured in carats. In 18 carat gold, copper makes up about 25 percent.
- While South Africa was the leading gold producer in the last 100 years, China has recently overtaken the African nation.
- Gold has been discovered on every continent of earth.
- It is widely believed that 80% of world’s total gold is still under ground.
- In 1912, Olympic gold medals were entirely made from gold but modern medals contain only 6 grams of gold.
- In late 1840’s, California was thronged by people looking for gold. The period is known as ‘Gold Rush’ and was started after discovery of gold at Sutter’s Mill.
- Romans began using gold coins in 50 BC and called them ‘Aureus’.
- NFL team San Francisco 49ers are named after the gold miners from the Gold Rush in 1849.
- Federal Reserve Bank of New York’s vault contains 25 percent of world’s total gold, making it the largest stockpile of gold.
- Even the purest form of gold (24k) has some amount of copper in it.
- After China, Australia, United States, Russia and Peru are the largest producers of gold. The world leader of yester years, South Africa has dropped down to 6th place in the list.
- Gold can be used as a food ingredient and gold flakes, dust and leaves are used as decorations for gourmet meals like sweets and drinks.
- Gold is also used to manufacture crowns and permanent bridges in the field of restorative dentistry.
- 75% of world’s total gold in circulation was mined after 1910.