Physical Properties of Gold
Gold is one of the few metals that can be found in pure form in nature. It does not usually form compounds with other elements. It is one of the rare metals that does not rust or oxidize at room temperature. It is incredibly malleable; 1 gram of gold can be rolled into a thin sheet over an area of more than 1 square meter.
Gold is a very good conductor of electricity, which is why it is used in sensitive electronics. It is an extremely dense metal; when dropped into water, it quickly sinks to the bottom. Gold has a melting point of 1064°C and a boiling point of about 2970°C. Pure gold has a slightly reddish-yellow hue; alloys can vary in color.
Historical and Cultural Significance
Gold is one of the first precious metals known in human history; it was used in Mesopotamia around 4000 BC. In ancient Egypt, gold was called the “skin of the gods” and was found in abundance in Pharaoh's tombs. In medieval Europe, gold was considered the most important indicator of power and wealth.
In China, gold has long been a symbol of good luck and prosperity. The Aztecs called gold “the excrement of the gods”; for them it was a sacred substance. Gold-based monetary systems (Gold Standard) were the basis of the world economy for many years.
Gold in Economy and Finance
The largest part of the world's gold reserves is stored in the US Federal Reserve's Fort Knox vault. Most of the gold used for investment purposes in the world today is in the form of bars and coins. Approximately 50% of the gold produced in the world is used in the jewelry industry, while 40% is held for investment purposes.
Gold in Nature
Most of the gold on the Earth's surface is the result of star explosions (supernovae) and neutron star collisions. About 20 million tons of gold is dissolved in the world's oceans, but its extraction is not economical. The Witwatersrand basin in South Africa is one of the largest gold deposits in world history. A significant portion of the world's gold has yet to be discovered deep in the earth's crust.
Strange and Fun Facts About Gold
There is very little gold in the human body; trace amounts are found mainly in the blood. Gold is edible; some fancy restaurants decorate dishes with gold leaf. The visors of space helmets are coated with a thin layer of gold to protect against harmful solar radiation.
According to the Guinness Book of Records, the world's largest gold bar is on display in Japan; it weighs about 250 kilograms. Olympic medals are not pure gold; today only their surfaces are gold-plated.
Mining and Production of Gold
The first gold mining activities in the world started in Egypt and Nubia. In modern mining, an average of only a few grams of gold is extracted from a ton of rock. Gold mining is one of the industries with the greatest environmental impact in the world. Cyanide leaching is widely used in gold mining to separate gold from ore. About 10% of the world's gold production is produced by small-scale, independent miners.
Gold in Technology and Industry
Gold is used in cell phones, computers and other electronics because it does not rust and is an excellent conductor. In spacecraft, gold is used for radiation shielding and temperature control. In medicine, gold nanoparticles are used in cancer treatments and diagnostics. In dentistry, gold alloys have been used as fillings and crowns for many years.
Gold Records and Curiosities
The world's largest gold mine is located in the Carlin Trend area in Nevada. The world's largest gold nugget is worth around 12 million dollars. If all the gold ever mined were melted down and put together, it would form a cube with sides of about 22 meters. India is the largest consumer of gold jewelry in the world. The “Welcome Stranger” nugget found in Australia is one of the largest natural gold nuggets ever found.
Chemical Properties and Reactions of Gold
Gold is insoluble in most acids except in a special acid mixture called aqua regia. Gold takes on a yellow color due to the electron configuration of its atoms. Gold alloys are formed by adding other metals (such as silver, copper, nickel) to pure gold. Gold can also be used as a catalyst in combination with platinum, but this use is quite expensive.
Symbolism and Mythology
In Greek mythology, the “Golden Fleece” is a symbol of great heroism and worth. In alchemy, gold was seen as the highest form of perfection and spiritual enlightenment. In the Chinese zodiac, gold is a powerful symbol of prosperity and happiness. In Norse mythology, gold is among the sacred treasures of the gods. In the Middle Ages, alchemists sought the “philosopher's stone” with the dream of producing gold.
Fun and Miscellaneous Facts
Most of the gold on Earth is concentrated in the Earth's core, but it is impossible to access. Gold has also been transported to Earth by meteorites, especially during the early Earth period. It can also be found on the surfaces of Mars and the Moon, but has not yet been mined.
The symbol for gold, “Au”, comes from the Latin word “Aurum”, meaning “the gleam of dawn”. Gold can change its color when alloyed with other metals, for example white gold or rose gold.
Environmental Impact and Recycling of Gold
The use of toxic substances such as cyanide and mercury during gold mining can seriously pollute the environment. Today, a significant portion of the gold used in jewelry, electronics and dentistry is recycled gold. Approximately 300 tons of gold is recovered annually from electronic waste. The concept of urban mining refers to the recovery of gold and precious metals from old telephones, computers and electronic devices.
Unusual Uses of Gold
Gold nanoparticles are used in some luxury skin care products and face masks. Gold leaves are used as edible decorations in specialty cakes and desserts. Several beer and liquor brands add gold leaf to their products to give them a touch of panache. Gold-based medicines have also been used to treat diseases such as rheumatoid arthritis. In the fashion world, luxury fabrics woven with gold threads have been produced.
Largest Consumers and Producers
China is the world's largest gold producer. Australia, Canada, Russia and the United States are also among the world's leading gold producers. Dubai is known as one of the global centers of the gold trade, nicknamed the “City of Gold”. India leads the world in annual gold consumption.
Rare Gold Phenomena
Pure gold can naturally form “dendritic” (tree-like) crystal structures. Gold is sometimes found in the form of natural alloys; for example, “electrum” is a natural mixture of gold and silver. Huge gold nuggets have been found above ground in Alaska and Australia in almost pure form. Gold sometimes deposits naturally as a thin film on other metals.
Records and Awards Involving Gold
When a musician sells 500,000 copies of an album, they are awarded a “gold record” in the US. Gold is not the main ingredient in Nobel medals, but they are gold-plated. The “Oscar” statuettes in Hollywood are made of gold-plated bronze.
Final Interesting Facts
Of all the gold mined in the world, 12% is found only in the jewelry of Indian women. Gold atoms are so dense that they can be woven into a rope as thin as 1/10,000th of a human hair. Some scientists predict that in the future gold could be extracted from space through asteroid mining. Gold can be recycled infinitely; it can be used again and again without any deterioration in quality.