Category Science

Around 1500 tons of gold are produced around the world every year. Most of this gold comes from South Africa. Two methods are used to extract gold from the rocks where it is found. Gold can be extracted using mercury. The minerals containing gold are mixed with mercury. The gold will dissolve in the mercury to form an amalgam or alloy of mercury. The amalgam is then filtered and heated so that the mercury evaporates, leaving pure gold behind. In another popular method, the minerals containing gold are added to a sodium cyanide solution.

This solution reacts with the gold to form a new compound. The solution is then filtered to remove impurities. Later, zinc is added to the solution which reacts with the compound to produce pure gold.

Picture Credit : Google

Gold played an important role in the life and culture of ancient Egypt. Ancient Egyptians considered gold divine and indestructible. It was associated with the brilliance of the sun and the sun god Ra was called ‘the mountain of gold’. Gold was widely used in ancient Egypt to make ornaments and other objects of value.

The pharaohs of ancient Egypt used gold lavishly in their tombs, on the floor, on the walls, and in the huge sarcophaguses or burial urns. It was their belief in the magic and spiritual power of gold that led the Egyptians to bury their dead adorned with golden amulets and jewels, making their tombs great treasure troves of gold.

No wonder, ancient Egypt was regarded as one of the richest countries in the world. In fact, Egypt was known as ‘the golden land’.

Picture Credit : Google

The practice of alchemy flourished in ancient civilizations and later, it gained popularity in Europe in the 19th century. The alchemists, people who practiced alchemy, searched for means to transform ordinary metals like lead into gold.

Alchemy flourished in the Middle Ages. This was due to the increasing popularity of gold. Kings, queens and common people desired gold alike. Furnaces were lit in gloomy basements of stone castles and secret experiments were performed with some mysterious liquids. Many alchemists believed that the purity of mind, body and soul was essential to pursue alchemy. They also believed that alchemy could prolong life.

In the Middle Ages, it was believed that a substance called the ‘philosopher’s stone’ could turn other metals into gold. Needless to say, no one ever discovered such a stone, nor did the experiments of the alchemists meet with any success.

Picture Credit : Google

We all are familiar with the stories where kings reward artisans, craftsmen and good subjects with gold coins.

Gold was used as currency in many kingdoms. But where was it used as currency for the first time? Lydia, an ancient kingdom in western Turkey is believed to be the pioneer of gold currency. Lydia was a fertile kingdom, but its greatest asset was the river Pactolus; it carried gold deposits.

Around 643 to 630 BC, the Lydians began producing the first coins. They were quite crude, and were made of electrum, a naturally occurring pale yellow mixture of gold and silver. By about 560 BC, the Lydians had learned to separate the gold from the silver following which, King Croesus issued the world’s first gold coins. Shortly afterwards, in 546 BC, King Croesus was captured by the Persians, who came to adopt gold as the main metal for their coins.

Soon, gold coins were being used in many other ancient countries. But the credit of introducing gold currency lies with the Lydians.

Gold secured a place in the hearts of early humans the moment the sparkling yellow grains were discovered for the first time. Humans have longed for gold ever since then. Men fought for it, women adored it.

We know the story of king Midas. According to Greek mythology, king Midas was granted the boon to turn anything that he touches into gold. He jumped with joy when the leaves and fruits that he touched turned into gold. However, he soon realized that the boon that he had asked for was in fact, a terrible curse.

He could not eat or drink, nor even wash his hands. Everything he touched turned into gold the moment he touched it. The boon was finally taken back after begging the gods for mercy.

The story of king Midas conveys the importance that was associated with gold. He asks nothing else but gold. Ancient kings and queens have always tried to amass as much gold as they could. This is why gold has been called the ‘king of metals’ and ‘the metal of kings’.

Picture Credit : Google

Iron was popular in ancient India. The extraction of iron in India dates back to the 4th century BC. Iron was used to make ornaments, weapons and buildings.

Indian smiths had developed many advanced techniques of processing iron that did not exist anywhere else in the world in those days. Expert craftsmen created many beautiful structures from iron which have lasted centuries without rusting.

In Delhi, there is a famous iron pillar that stands testimony to the high level of skill achieved by ancient Indian ironsmiths. In fact, it has withstood corrosion for the last 1,600 years! This pillar had sparked the interest of many material scientists across the world.

The iron beams in the Surya temple at Konarak in coastal Orissa, and the iron pillar at Mookambika temple are also examples of the skill of the ancient ironsmiths in treating iron so that it became rust- resistant.

Picture Credit : Google