Amazing Facts About Gold
Amazing Facts About Gold:
Gold is a dense, soft, malleable, ductile, yellowish, shiny metal with the symbol Au (Au is the first two letters of the Latin word ‘Aurum’ which means ‘gold’) and atomic number 79. Since the beginning of human history, it has been a highly sought precious metal for coinage, jewellery, and other arts. Generally gold occurs as nuggets or grains in rocks, veins and alluvial deposits. Gold has served as a symbol of wealth and as a store of value throughout human history. Gold standards have provided a basis for monetary policies. It also has been linked to a variety of symbolisms and ideologies.
As of 2009, a total of 165,000 tonnes (one tonne = 1000 kg) of gold have been mined in human history. This is approximately equivalent to a cube of side 20.4 m (volume 8,500 m³) . About 50% of new gold produced is used in jewelry, 40% in investments and 10% in industry.
Gold has many uses. It is used in the fields of dentistry, electronics etc. It is highly useful because it is resistant to corrosion and is an excellent conductor of electricity.
Gold is a transition metal. Pure gold is chemically inert when compared to other metals. It is resistant to individual acids. However it is attacked by the acid mixture aqua regia (A mixture of freshly prepared concentrated nitric acid and concentrated hydrochloric acid in a volume ratio of 1:3 respectively). Gold also dissolves in mercury, forming amalgam alloys. It dissolves in alkaline solutions of cyanide. However, gold is insoluble in nitric acid. This property of gold is used to confirm the presence of gold in many articles. Common oxidation states of gold are +1 and +3.
Gold is one of the naturally occuring highest atomic number elements. It is thought to have been formed from a supernova nucleosynthesis process. On our planet, elemental gold often occurs as gold silver alloy. Such alloys usually have a silver content of 8–10%. Electrum is elemental gold with more than 20% silver.
Gold NuggetsGold is obtained from gold ores. Gold ores are often found together with sulphide or quartz minerals. Native gold is found in the form of free flakes, grains or larger gold nuggets that have been eroded from rocks and ended up in alluvial deposits.
Gold has only one stable isotope, 197Au, which is also its only naturally occurring isotope. Radioisotopes of gold have also been synthesized. The most stable radioisotope of gold is 195Au. It has a half-life of 186.1 days. The least stable radioisotope of gold is 171Au. It has a half-life of 30 µs. Most of gold’s radioisotopes with atomic masses below 197 decay by some combination of proton emission, α decay, and β+ decay. The exceptions are 195Au, which decays by electron capture, and 196Au, which decays most often by electron capture (93%) with a minor β- decay path (7%). All of gold’s radioisotopes with atomic masses above 197 decay by β- decay.
Gold is the most malleable and ductile of all metals. An ounce of gold can be beaten into a sheet of 300 square feet. A single gram of gold can be beaten into a sheet of 1 square meter. Gold leaf can be beaten thin enough to become translucent. Light transmitted through translucent gold appears greenish blue. This is because gold strongly reflects yellow and red. Such semi-transparent sheets also strongly reflect infrared light. This makes them useful as infrared shields in visors of heat-resistant suits and sun-visors of spacesuits.
Gold is a good conductor of heat and electricity. It strongly reflects infrared radiation. Chemically, it is unaffected by air, moisture and most corrosive reagents. As a result, it is used as a protective coating on other more reactive metals. It is also well suited for use in coins and jewelry. Gold readily forms alloys with many other metals. These alloys are produced to modify the hardness and other metallurgical properties, to control melting point or to alter the color.
Since ancient times, gold has been a highly valued metal in many societies. Gold may symbolize justice, balance, intelligence, power, strength, perfection, hope, wealth, warmth, happiness, etc.