Gold

Gold (chemical symbol Au, from the Latin aurum) is a precious metal with atomic number 79. It is yellow-red in colour, highly malleable compared to other metals, and does not tarnish or react with air and water. For this reason, gold objects made thousands of years ago are still found in ancient tombs gleaming.

Gold belongs to the group of noble metals. It conducts electricity and heat well and is the most malleable of all known metals—a single gram of gold can be drawn into an extremely long wire or beaten into very thin foil. Its uses fall into three categories: financial reserves, jewellery, and electronics and medicine.

Physical and Chemical Properties

Gold is a dense metal—a volume of it has much greater weight than common metals. It glows at extremely high temperatures. Chemically it resists most acids, but a mixture of nitric and hydrochloric acids (known as aqua regia) dissolves it. The purity of gold is measured in carats: 24 carats means nearly pure gold, while 18 and 14 carats are alloys with other metals such as copper or silver to increase hardness.

Mining and Extraction

Gold is found in rock formations beneath the earth (hardrock mining) and also in river sediment through panning. Modern methods mostly involve crushing rock and then using chemicals to separate the gold—a common practice with environmental risks. The largest producing countries include China, Australia, Russia, and South Africa. Artisanal small-scale mining occurs in many parts of Africa and is often associated with mercury use, which has health hazards.

Economic Role

For a long time gold formed the basis of the world's monetary systems, with some currencies exchangeable for a fixed amount of gold. This system ended in the twentieth century, but central banks in many countries still hold gold reserves. In financial markets, gold is seen as a safe asset when currency prices fluctuate or political instability exists; its price changes daily on the global market.

History and Culture

Gold is among the earliest metals used by humans, because it naturally occurs in pure form without smelting. Ancient Egypt, Mesopotamia, India, and West African kingdoms used it as a symbol of power and divinity. Gold trade across the Sahara strengthened kingdoms such as Mali. Today, gold remains a significant part of wedding customs and family wealth-keeping in Asian and African societies.