Diamond Education

What is a diamond?

Carbon is the only element in diamond. Impurities such as boron and nitrogen can also be found, although they are not part of the chemical structure. The unique properties of diamonds are a result of its crystal structure. Diamond is the hardest material known to man and is also the least compressible with stiffness like no other.

How are natural diamonds formed?

Contrary to popular belief, diamonds are not formed by compressed trees and vegetation, such as coal. The core processes of forming diamonds involve extremely high temperatures and massive amounts of pressure. These conditions can be achieved deep under the Earth’s surface, around 100 to 120 miles below. Temperatures at this depth can reach as high as 1300 degrees Celsius. Combined with pressure, the carbon atoms crystallise in a cubic arrangement thus creating diamonds. From deep inside the Earth, the diamonds are forced upwards using magma flow as a transporter. The age of a diamond

It may come as a surprise that the youngest diamonds on earth are around 1.2 billion years old, the oldest being 3.3 billion years old, close to the birth of planet Earth. Scientists studying in South Africa believe that there have only been two or three occasions in the Earth’s history when diamonds have been made, all of which happened billions of years ago.

Coloured diamonds

Fancy coloured diamonds are around ten thousand times rarer than colourless diamonds. The natural processes used to create colourful diamonds happen very rarely. Natural radiation and pressure can result in a diamond acquiring a specific colour, although more commonly, a diamond obtains colour through the intervention of another element during its creation. Examples of these colour-giving elements are boron and nitrogen.

Where and how are diamonds mined?

Diamonds are mined in countries all over the world: Angola, Botswana, South Africa, Congo, Zimbabwe and Tanzania are just some of the countries in Africa with large diamond mines. Russia and India also have accredited diamond mines. Other countries mining diamonds include the USA, Canada and Australia.

There are several methods used to effectively mine diamonds. Methods vary depending on the distribution of the diamonds and the lay of the land. Open-pit diamond mines are used when tunnelling is not an option. The diamonds are amongst gravel, sand and other loose material near to the surface.

Placer mining is used to extract diamonds from alluvial, eluvial (residual deposits of soil) and colluvial (loose rock) deposits, achieved mechanically and hydraulically with the use of machines. Sifting by hand is another process used in placer mines. Hard rock mining is the process used in the excavation of minerals containing metals, and the same process is adopted for mining diamonds and gemstones. This method uses deep underground tunnels to reach the diamonds.

Choosing a diamond that's right for you

When selecting a diamond you should consider the four Cs: Cut, Colour, Clarity and Carat Weight. By finding a good balance between these characteristics you can make an informed decision on which diamonds to choose.

Cut (shape)

The brilliance of a diamond is dependent on the cut. Quality diamonds must be professionally cut, and not spread. "Spreading" is an improper practice which compromises the proper proportions of the diamond to make it increase in weight. A classic round, brilliant cut diamond has 58 facets: 33 on the top, 24 on the bottom, and the culet, which is 1 point at the bottom. Every one of these facets has to be placed in exact geometric relation to the next when the stone is being cut.

Colour

When viewed under a jeweller's loupe, most diamonds contain slight traces of light brown or yellow pigment. Colourless and near colourless diamonds are much more valuable, and taking the stone's size into consideration, a single increase in colour grade can raise the value of a diamond by thousands of pounds (or dollars) per carat. Engagement rings traditionally use diamonds that are colourless, or near colourless.

Diamonds can be naturally found in shades of blue, green, red, pink and deep yellow. These are known as fancy diamonds. Worldwide, colourless diamonds are graded using an alphabetical scale. Colourless or rare white diamonds are graded D, E and F - the most valuable being the D grade, which is extremely rare.

Clarity

The clarity of the diamond depends on the number, size and location of inclusions found in the stone. Under the magnification of a jeweller's loupe, imperfections or trace minerals can be seen in the stone. These are called inclusions. The diamond will increase in value when there are fewer inclusions present, and will be clearer and more brilliant. A diamond with no inclusions is extremely rare and valuable, and is given the term flawless.

Carat Weight

Judging a diamond on the carat weight alone can be very misleading. The cut, clarity and colour of the diamond are extremely important and have to be taken into account. A large stone will not generally be valuable if it lacks purity, high grade colour and brilliance. However, as larger stones are rarer than smaller ones, the value will rise exponentially with carat weight, making a 3.0 carat diamond worth more than three 1.0 carat diamonds of equal quality.

So, when making your decision as to which diamond to buy, it is important to take all the above factors into account. Remember the four Cs: Cut, Colour, Clarity and Carat Weight.

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