If you are thinking of investing in diamonds this article aims to give you some background information about the different types of diamonds: including, an understanding of the differences between industrial diamonds and synthetic diamonds.
What is a diamond made of?
While a diamond may be forever according to the famous De Beers marketing campaign, this highly desirable piece of jewellery had a much more prosaic beginning.
A diamond is a crystalline form of carbon and has the highest thermal conductivity and hardness of all known natural materials.
Most natural diamonds were formed between 1 billion and 3.5 billion years ago deep in the earth’s mantle when carbon was subject to extreme pressures and temperatures.
Many millions of years later they were brought to the surface in deep, violent volcanic eruptions that formed volcanic pipes much sought after by diamond miners.
Small diamonds are formed in subduction zones and by asteroid impacts. They also occur on meteorites and making synthetic diamonds in a laboratory is now a routine process.
While natural diamonds are relatively rare on the earth’s surface, deep within the earth, they are abundant. An estimated quadrillion tonne of diamond is buried deep inside the planet.
What are the different types of diamonds?
1. Industrial diamonds
Many industrial processes require the mechanical properties offered by a diamond. The most common applications are diamond abrasives, cutting tools and drills.
Natural industrial diamonds are mined diamonds that are either too small or too badly flawed to be used as gemstones. The primary sources of industrial diamonds are:
- Bort: large grey-black diamonds characterised by flaws and inclusions. These are crushed and used for abrasive grits for grinding wheels; diamond impregnated saws, and lapping and polishing.
- Ballas: also known as short bort, it consists of tiny diamond crystals which are known for their toughness. It is used for similar purposes as bort.
- Carbonado: black opaque diamond, it is slightly porous and resistant to cleavage. It is used mainly in drills and cutting tools. It is also used for vinyl record player needles.
Industrial diamonds may also be synthetic.
2. Synthetic diamonds
Synthetic diamonds are created in the laboratory by applying very high pressures and temperatures to graphite. They can also be synthesised using vacuum vapour deposition processes.
They have similar properties to natural diamonds including hardness, transparency, high thermal conductivity, and high electrical resistance.
Their main applications are as grits and abrasives and hard coatings. They are also used in electronics as substrates for semiconductor devices.
Doped synthetic diamonds are also used as semiconductors in high-temperature electronics.
3. Blood diamonds
Blood diamonds, more correctly called conflict diamonds, are diamonds used to finance civil wars. The definition applies to diamonds mined in war zones and then sold to fund an insurgency.
Investing in diamonds
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