Diamonds of Physicochemical properties

Diamonds of Physicochemical properties

January 6, 2021 Off By Rob Prosser

Diamonds are a cubic polymorphic modification of carbon. This is one of the amazing properties of nature – from the same elements under different conditions to create substances that are not similar to each other. Graphite is another crystalline form of carbon and has opposite qualities. It is black, fragile, and easily soiled. It can be used to make crucibles, lubricants, and pencils. Under normal conditions, diamond and graphite show no attempt to change from one form to another. In order for the diamond to acquire a dark hue, it must be heated in a vacuum to a temperature of 1500Co.

Pure carbon has no color – these are absolutely transparent crystals, but metal impurities color the mineral in different colors. The mineral can be artificially colored by irradiation with neutrons or electrons. So it turns green or blue and does not lose color even when heated.

The properties of the diamonds stone are described in the table:

Color: Colorless, green, black, blue, yellow, red.

Luster: Diamond

Transparency: Transparent to Opaque

Mohs hardness: 10

Density g / cm3: 3.5

Refractive index: 2.4

The main property of the mineral is hardness. It ranks highest in the Mohs classification. Below it is a corundum with an indicator of 9 units, but there is a huge difference between them. The diamond is 180 times harder. But this does not mean that it is very durable. If the stone is hit, it will split parallel to the edges along with the cleavage directions. 

The myth about the strength of the diamond let down the mercenaries of Louis XI, who seized the jewels of Charles the Bold. They, checking the authenticity of the stones, split most of the treasury. After making sure it was glass, they threw away the debris. The property of diamond to crack was used by the mineralogist. He cheaply bought samples that were not faceted due to internal defects or irregular shapes, split them, and sold the fragments as separate crystals.

The combination of hardness and a high degree of light refraction add up to this recognizable diamond brilliance. Some stones tend to glow in the dark after being exposed to the sun for a long time. Sometimes, if you rub a stone, it begins to emit a weak light.

The extracted samples are not lost. Pure and transparent crystals are polished to become luxurious jewelry. It is now the most expensive gemstone, the standard of brilliance and hardness. Less valuable samples are used in production. They are inserted into drill bits, engraving needles, glass cutters. Diamond grit is used as an abrasive for grinding.


The history of the diamond began in India. Koh-i-nor is mentioned in sources that are 3 thousand years old. The Vedas describe a place illuminated by diamonds and rubies, which were similar in brightness to planets. He is also mentioned in poetic poems. Even then, they studied its properties: hardness, durability, and refractive properties. They dedicated him to their most revered gods and decorated their festive garments.

He appeared in the West later. Theophrastus does not mention him in his “Treatise on Precious Stones”; it turns out that at the beginning of the 3rd century BC Western science did not yet know about him. It appeared between Theophrastus and Pliny, at the end of the 3rd century. Probably as a result of the campaigns of Alexander the Great, when communication with India was established.

Borneo is the second country after India to discover diamonds. But the account of the extracted mineral was almost not carried out. All raw materials were handed over to the Rajs, on the territory of whose principalities stones were found.

The next diamond country was Brazil. A priest from India who came to Brazil found it in gold ore. Later there were other deposits. Since then, Brazil has been one of the world’s first diamond suppliers.

In the 19th century, diamonds were found in Africa on the banks of the Orange River. Prior to that, local residents considered them to be talismans. It is said that an African farmer picked flints out of bricks at home and brought them to a local store to sell. As it turned out, he was trying to sell diamonds for next to nothing. Another case tells that local children loved to play with colored stones, which turned out to bechalcedony, cornelian, agate, and pomegranate. The boy was even lucky to find a 21-carat stone. Now Africa supplies the bulk of diamonds to the world market.

Another article on this blog that might interests you:

Diamond: Properties and uses