Since the beginning of its history, human beings have been fascinated by adorning themselves with jewels. The first ones were made with pieces of shells, bones and shiny stones. Later, he discovered the beauty of precious gems set in copper, silver or gold pieces. And, over time too, men learned how to please women by giving them jewelry.
Although everyone thinks precious gems are wonderful products of nature, many have no idea how they are formed. So keep reading and learn how the curious formation of these minerals happens! Check out!
The concept of precious gems
Only four stones in the world are classified as precious gems, namely emeralds, diamonds, rubies and sapphires. This concept has its origins in Ancient Greece, Rome, Egypt and Mesopotamia, where they had ceremonial and historical importance. They were named “cardinal gems” due to their use by royalty and religious figures.
Historically, the gemstones are valued for their extreme rarity, and large stones with fantastic colors have always been unusual and very faces. The amethyst stone was also considered one of the cardinal gems until the XNUMXth century, when a large source found in Brazil made it more accessible.
Today, “precious stone” is a subjective term, which is used solely by tradition. A gemstone can be less expensive and more abundant than certain semi-precious stones.
The Formation of the Diamond
First of all, it is necessary to understand that all precious stones are found linked to other minerals, and only later are they separated and polished. Minerals form because of the Earth's diverse conditions, and most precious gems form in the Earth's crust: the most superficial layer of the planet, with a depth of 5 to 40km.
O Diamond, in turn, is formed in the Earth's mantle, a deeper layer, which represents 80% of the planet's volume and is where the magma is, material that flows in the form of volcanic lava. Therefore, most diamonds form under extreme pressure and very high temperatures, often at depths of over 140km within the Earth's mantle.
On average, diamond formation takes place over periods of 1 to 3,3 billion years, until they come to the surface through volcanic eruptions, which bring magma up from the deepest places on Earth. It's a rare type of magma called a kimberlite.
Diamond's resistance is so great due to the arrangement of its molecules. And, in addition to this precious gem, only a stone called peridot is also formed in the Earth's mantle.
The Formation of Sapphire and Ruby
These two precious gems are found in so-called metamorphic rocks. They are formed in the following way: magma erupts from the mantle, and then volcanism puts the rocks from where it erupted under heat and pressure, which can cause changes in the chemical structure of their crystals. Hence the name metamorphic, due to the chemical transformation that these rocks undergo.
It's a process that takes millions of years and few places in the world have mines of these rare crystals. In addition to ruby and sapphire, gemstones associated with metamorphic rocks include beryl, jade, lapis lazuli, turquoise, spinel and zircon.
Emerald's Formation
The emerald is a gem found in rocks called igneous. The formation process of these rocks involves the solidification of magma. It can rise into the crust, usually through volcanoes, and when it reaches the Earth's surface, it turns into lava and solidifies.
However, if it cools slowly in the crust, it can crystallize and form minerals. Increases in pressure can also cause magma to seep around rocks, often doing chemical exchanges with them. And so minerals such as emerald are formed, which is actually a variety of the mineral beryl.
As you could see, the formation process of these stones justifies their preciousness. And, to better understand how your training takes place, you can watch a National Geographic channel video, where the whole process is explained step by step.
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