To date, around 244, 000 metric tons of gold have been discovered (187, 000 metric tons historically produced plus current underground reserves of 57, 000 metric tons). During the formation of the Earth, molten iron sank to its center to form the core. This took with it the vast majority of the planet's precious metals, such as gold and platinum. In fact, there are enough precious metals in the core to cover the Earth's entire surface with a layer four meters thick.
All the gold found on Earth comes from the remains of dead stars. As the Earth formed, heavy elements such as iron and gold sank toward the planet's core. If no other event had occurred, there would be no gold in the Earth's crust. But, about 4 billion years ago, the Earth was bombarded by asteroid impacts.
These impacts agitated the deepest layers of the planet and forced some gold to enter the mantle and crust. On Earth, gold finally came to us about 200 million years after the planet formed, when meteorites filled with gold and other metals bombarded its surface. Under this gold standard, anyone could present paper money to the government and demand an equal value of gold in return. The carat weight of gold is indicated by a number, followed by a “c” or “ct”, which indicates how much metal a piece of jewelry is gold.
Gold is the highly efficient conductor that can carry these small currents and remain free of corrosion, which is why electronic products made with gold are very reliable. Cyanidation is the most popular and involves oxidizing and dissolving gold in alkaline cyanide and separating the resulting gold solution from solids. Once gold has been found and extracted from its source, whether it is a dedicated gold mine or not, it needs to be processed so that it is ready for use in gold jewelry. Once gold has been processed and refined, it is ready for use in any product for which it was mined, be it electronics, dentistry, aerospace or any other application of gold.