What are the oldest precious stones on the earth?
What are the oldest precious stones on the earth? Have you ever asked yourself this question? What gemstones are found deeper and how do they reach the surface? The best-known gemstones are diamonds, highly sought after for their beauty. The most curious thing is that it is not yet fully understood how they are formed, but laboratory experiments show that gemstones crystallize only under extreme pressures.
Most natural stones have been traced to the upper mantle, at depths between 150 and 300 km, where pressures can reach more than 20,000 atmospheres.
How diamonds form is not yet understood, but experiments show that gemstones crystallize only under extreme pressures. For a long time, this caused diamonds to compete with a gem called peridot for the title of deepest gemstone. Peridot is the gem form of a mineral called olivine that makes up more than half of the upper mantle, which extends from the base of the crust up to 410 km.
But in 2016, scientists described a collection of superdeep diamonds from about 660 km, and another batch in 2021 was determined to come from a depth of 750 km, Live Science reports.
It was difficult to say whether the diamonds or the peridot were deeper, but that settled the debate. To arrive at those estimates, researchers studied the diamonds’ crystallization patterns, as well as their inclusions: bits of minerals or fluids buried in the gems since they formed.
Inclusions of a mineral called bridgmanite and fusion of iron, nickel, carbon, and sulfur told scientists that these super-deep diamonds probably formed in the lower mantle, which is about 75% bridgmanite, and that they grew from liquid metal surrounded by methane. At these depths, pressures can exceed 235,000 atmospheres.
Some estimates suggest that diamonds found on the surface today may have formed up to 3.5 billion years ago. Diamonds are also believed to be extremely old. Some estimates suggest that diamonds found on the surface today may have formed up to 3.5 billion years ago, although many are much younger.
Its longevity is attributed to the strength of its chemical bonds. Diamonds are made of carbon, and because they form under pressure, it takes a lot of force to break their bonds. And, what is the deepest well that humans have ever reached inside the Earth? In the Kola superdeep well in Russia, it barely skimmed the surface, just 12.6 km deep. Diamonds are brought to the surface thanks to a unique type of magma called kimberlite.
Kimberlite magmas tend to be volatile, over 100 feet per second (30 meters per second), and pull diamonds from surrounding rocks as they go. In this way, gemstones that were formed over billions of years come to the surface within months or even hours.
In many cases, diamonds are the only source that researchers have to understand the composition of the planet’s interior and the processes that take place there. In addition to their aesthetic value and hardness, diamonds are often of interest because they are the only source that they have.
researchers to understand the composition of the planet’s interior and the processes taking place there. By studying these gemstones, scientists have learned that the early Earth was not as tectonically active as it is today. It has also been discovered that the carbon cycle comes from within the Earth and even completely new minerals were found in the past.
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