The word diamond comes from the Greek “Adamas” – unsurpassed. Scientists have not come to a consensus on the origin of diamonds. According to the most popular hypothesis, the mineral was formed as a result of the cooling of silicates in the mantle of the earth’s crust. And it owes its appearance on the surface of the planet to a series of powerful underground explosions.
Diamonds in nature are inclusions in mountain olivines, serpentines and graphites… In addition, they are sometimes found in river and sea coastal pebble placers, where they get as a result of the destruction of volcanic rocks. To obtain one carat of natural diamonds, it is necessary to process about 250 tons of diamond ore. Considering that, on average, a nugget loses half of its weight during cutting, the number of ore required can be doubled.
In terms of chemical composition, it is one of the simplest minerals, it is pure carbon with minor impurities of calcium, magnesium and iron oxides.
Physical and chemical properties of diamond
- Chemical formula – C (carbon).
- Color – colorless, with shades of yellow, less often – red, orange, green, blue.
- The crystal system is cubic.
- Hardness 10 on the Mohs scale.
- Density, specific gravity – 3.52 g per cm3.
- The fracture is conchial.
- Refractive indices – 2.417.
- Cleavage is perfect, octahedral.
- Habitus, crystal shape – octahedral, dodecahedral.
- Pleochroism is not.
- Transparency – from transparent to opaque.
Where and how are they mined?
The main diamond deposits are concentrated in Australia, South Africa, Congo and Russia. These countries account for about 60% of the world’s mineral production. Botswana, Angola and Namibia also have significant reserves. Until the end of the 17th century. almost all diamonds were mined in the mines of India, but today they are almost completely devastated.
Legend has it that in ancient times people used birds of prey to mine diamonds. Pieces of raw meat were thrown into deep crevices with precious placers, to which small crystals adhered. Smelling the smell of prey, the eagles descended into these crevices, grabbed food and carried it away in their claws. After that, it remained to follow the bird, sneak up imperceptibly and snatch out the meat with the jewels adhered to it. The second method involved searching for eagle’s nests, around which a large number of bird droppings gathered. People picked it up and took out diamond nuggets, sometimes reaching considerable sizes.
In fact, in the old days, diamonds were mined only from the river and sea placers by carefully washing out pebbles and sand. The main tools were a shovel, sieve and pick. An alternative to this method was the discovery at the end of the 19th century. A kimberlite pipe is a geological body of vertical shape, formed by the breakthrough of gases through the earth’s crust. Kimberlite is a volcanic rock in which diamond crystals are found along with other minerals. Today, almost the entire diamond mining industry is built on the use of this natural phenomenon.
Interesting facts and features
Each diamond has a unique structure and characteristics. Two identical stones, like two identical fingerprints, do not exist. The widespread myth that a diamond cannot be broken once played a cruel joke with the Swiss mercenaries of King Louis XI. During one of the many internecine conflicts, they seized the jewels of Duke Charles the Bold. Having heard about the extraordinary hardness of diamonds, the war decided to check the authenticity of the stones. The diamonds could not withstand the powerful blows of the hammer and crumble. A huge amount of jewellery was thrown away because the Swiss considered it to be fake. At the end of the 15th century. The Archduke of Austria, doubting the bride’s positive answer, heeded the advice to back up his intentions with jewellery.
How to distinguish fakes
Without exception, all diamond buyers are afraid of being deceived. In doing so, they tend to pay the lowest possible penalty for the stones. Fraudsters and dishonest traders successfully play on these conflicting feelings. The most common attacker ploy is to replace gems with cheaper counterparts. To imitate diamonds, they usually use transparent zircon, colorless sapphire, or ordinary crystal. To identify a fake, you need to look through the stone at the sun. A cut diamond reflects rays in such a way that only a bright point can be seen through it. L imitators let light through completely.
In addition, counterfeit sellers often mention the popular myth of the complete transparency of diamonds in the water. In fact, this is fiction. The invisibility effect can be achieved between those materials that have the same refractive index. The refractive index of water is 1, that of a diamond is 2.4. Of all the diamond imitators, the closest in this characteristic to water is ordinary glass, the refractive index of which is 1.5. Thus, a real stone, lowered into a glass, will continue to sparkle, but a fake one will not.
It is almost impossible to distinguish a natural diamond from one created in the laboratory. The advanced technology allows synthesizing of artificial diamonds weighing up to 15 carats. In such a situation, the buyer should be confused by the obviously low price, which may be ten times less than the real one. There are no objective reasons for selling diamonds for a song.
An interesting way to identify a fake was invented by the French chemist Margot. The scientist proposed to determine the true diamond by sliding an aluminium stick along its surface, having previously wetted the stone with water. On rhinestones, the metal will leave a clear, silvery line that is very difficult to erase. And on a natural diamond, no trace of aluminium will be visible. Only a professional appraiser can guarantee 100% authenticity of a diamond. Well-known tips and tricks will only help to identify a low-quality fake.
Processing and use
Diamonds are most widely used in the jewellery industry. But few people know that not every stone is of gem quality. No more than 15% of mined minerals are suitable for creating a diamond, another 45% of nuggets are considered conditionally suitable for cutting. The remaining 40% of diamonds are used as composite materials and superhard elements for industrial purposes. The most common diamond cuts are brilliant cut and rose cut. The first is used for processing large nuggets, the second is for small diamonds.