Gold has emotional, cultural and financial value, and different people around the world buy it for a variety of reasons.
It also has unique properties as a metal, with reliability and versatility that make it indispensable in engineering and electronics. Since it conducts electricity, is resistant to corrosion and is biocompatible, its most recent application as a nanomaterial offers new solutions for a range of global health and environmental challenges.
Throughout history, it has been treasured as an object of natural beauty and radiance. For that reason, many cultures, such as the Egyptians, felt that gold best represented the sun. The elemental symbol of gold is Au – and it comes from the Greek word “aurum”, which means “glow of sunshine”.
Hallmarking gold jewellery also became a form of consumer protection, dating back to King Louis IX of France and Edward I of England in the 13th century. Their prescribed mark, and subsequent ones for individual goldsmiths and production dates, became a prerequisite for any gold offered for public sale.
Over the past two decades, China has become the world’s leading gold market. Gold in China currently accounts for about 35% of overall global supply and demand, and for 28% of the world’s jewellery. As both the largest consumer and producer of it in the world, China plays a key role in perpetuating and protecting gold’s future on the planet. Remarkably, that echoes the country’s first interactions with the substance: in the realm of medicine.
Indians and Egyptians used gold-based medicinal preparations, but China seems to have been the earliest to cure sickness with it, dating as far back as 2500 BCE. Since the discovery of gold, people thought it had an immortal nature, given its resistance to chemical corrosion, and associated it with longevity. In Huan Kuan’s On Salt and Iron (81 BCE), it’s stated that “immortals swallow gold and pearls, so that they enjoy eternal life in heaven and on earth”.
Indeed, gold became the Eastern Jin Dynasty’s (317–420 CE) “superfood”. In scholar Ge Hong’s Baopuzi: Gold Elixir, he wrote that to eat gold “tempers the body of a human being, and he enjoys eternal life”. Alchemist and writer Wei Boyang of the Eastern Han Dynasty (22–220 CE) wrote in Zhouyi Cangtong Qi: “it is the most valuable thing in all the world because it is immortal and never gets rotten. Alchemists eat it and they enjoy longevity.”
Though people in ancient times knew very little about gold’s immortal nature from the perspective of science, they were curious about its effect on human life. Thus, it took on a therapeutic role in China, and was widely used by physicians and surgeons. Pure gold was used to treat furuncles, smallpox and skin ulcers, and to remove mercury from skin and flesh; some ancient references noted that gold drugs could cure joint disease and disease in lungs. There were also prescriptions containing it for curing measles and other diseases. Plant and animal medicines were used in ancient prescriptions, and many of these contain it as a trace element.
Contemporary analysis reveals that the horns of the rhinoceros, antelope, deer and other species contain traces of it. It’s believed the substance concentrates in protein (such as in the horns and hair), possibly as gold-protein complexes. Many medicinal herbs contain a trace of it and their extracts might contain a trace of a gold complex that could cure sickness.
That efficacious effect is still very much at work today in nanotechnology. Gold has an ability to reflect infrared radiation, which is one reason that physicians, scientists and researchers use the element to track down cancer cells and other microscopic items. In essence, gold’s nanoparticles are suitable for “staining” or making contrasts in cells appear more visible, such as in tissue samples. And because it is generally unaffected by most acids, bases and oxygen, scientists can be sure that golden nanoparticles won’t react with other agents and corrupt their readings.
Gold has the highest corrosion resistance of all metals, and is corroded only by a mixture of nitric and hydrochloric acid. Because it doesn’t oxidise, it has always been known as a “noble metal”. It’s the most efficient metal for the transmission of heat and electricity, and it’s also the most malleable of all metals. Gold’s one ounce can be drawn out into more than 80 kilometres of thin gold wire, or beaten into a sheet covering nine square metres. We’re dreaming of fields of it.
- Gold’s boiling point is 2,808 degrees Celsius.
- The average temperature of the human body is 37 degrees Celsius. Gold’s conductivity of heat means that it rapidly reaches body temperature – one of the reasons it has become valued for jewellery.
- Around 187,200 tonnes of golds have been mined since the beginning of civilisation.
- Even at only 10 parts of it per quadrillion, the world’s oceans are estimated to hold up to 15,000 tonnes of gold.
- Julius Caesar gave 200 gold coins to each of his soldiers from the spoils of war in defeating Gaul.
The article is originally published at China Daily.