So, this a big topic to cover. Let’s start with an easy question first - what actually are diamonds?
A diamond is a naturally occurring mineral made from carbon - essentially a rock. Their chemical make up is one of things that makes them so unique - each carbon atom is surrounded by four more carbon atoms and are connected through strong covalent bonds. This chemical arrangement makes one of the strongest, most durable and most versatile materials we have ever known, also making it the hardest known natural matter. This can be seen when looking at diamond on a MOHs Scale where it scores the highest - a 10. As well as their unique chemical make up they also have particularly special optical properties such as a high index of refraction, high dispersion and adamantine luster - the highest luster observed in minerals.
Diamond Chemical Structure
A common mistake around diamonds - which is still taught in my classrooms today - is that just because diamonds are composed of the element carbon that they must have formed from coal. This is not true! Diamonds are not native to our surface - they form at high temperatures and pressures in the Earth’s mantle about 100 miles below our surface. Many of the diamonds we see have been delivered to our surface through a natural phenomenon such as volcanic eruptions. These eruptions begin in the mantle and on their way up will tear out pieces of mantle rock and deliver them to the Earth’s surface without melting. These blocks are called xenoliths and they contain diamonds that were formed in the high pressure and temperature of the mantle. Sometimes these rocks can be found in sea or riverbeds where a storm has carried them from the volcano elsewhere.
Now we’ve looked at what diamonds are, we can look at what diamonds are used for. Although pretty, they aren’t just used for jewellery and it’s not hard to see why. Diamonds are used in medical technology all the time. One way is for a cancer screening - tiny nano diamonds can help detect the early stages of cancer by something called hyperpolarisation. This is where the atoms inside of a diamond align to make it detachable on an MRI - when these diamonds are attached to molecules that target cancer, they revel it’s exact location! Another way diamonds help us medically is by penetrating cell walls to delivery drugs without causing any damage - this use has been applied in many chemotherapy treatments. Diamonds are also used in the industrial world. Due to their physical properties, diamonds are a top choice for many industrial uses. One of the most common is their use in drill bits and saw blades to enhance durability and power - this even extends to jewellery cutting! They can also be used to heat sinks, due to their thermal conductivity. One of the first industrial diamond uses was as a heat sink for telecommunication components. Diamonds are also used in audio equipment because of their unique molecular structure it means they can deliver a high frequency, this is because the material is both hard and light enough to move the air around it without warping due to the pressure. More commonly, diamond will be used as the tip of the needle or stylus in a record player.
Now, when looking at diamonds particularly when it comes to jewellery it’s important to look at the 4 Cs. These are; Cut, Carat, Clarity and Colour. So let’s go into each one with a little more detail. Cut relates to - yep you guessed it - the cut of the diamond. In order for a diamond to have light pass through it, which makes it so sparkly, it must be cut in a particular way. This one is the most complex of the 4 Cs but definitely the most important - the cut of a diamond has a knock on affect for all the other Cs. Most believe the cut refers to the actual shape of the diamond but it actually means the way the stones facets interact with the light. An expert will examine the stone and determine how the proportions, symmetry and polish look and if they maximise the overall brilliance and sparkle. The most crucial is how the facets influence the brightness, fire and scintillation. Onto Carat - this is named after the carob seeds that early traders would use as counterweights, carat literally refers to the weight of the diamond. The metric weight for a diamond is the same all around the world - 200mg per carat. Normally, the larger the carat weight the pricer diamond however it does depend on what the other 3 Cs are looking like. In 1.00 carat there are 100 ‘points’ - so in a 0.25ct diamond there will be 25 points and jewellers might describe it as a ’25 pointer’. Next is clarity - this refers to the absence of imperfections found in a diamond.
TIP: Inclusions means the imperfection internal and blemishes means it’s external.
As always - the higher the clarity, the better the diamond. The GIA Diamond Scale has 6 categories. They are as follows:
- Flawless (FL) No inclusions and no blemishes visible under 10X magnification
- Internally Flawless (IF) No inclusions visible under 10X magnification
- Very, Very Slightly Included (VVS1 and VVS2) Inclusions so slight they are difficult for a skilled grader to see under 10X magnification
- Very Slightly Included (VS1 and VS2) Inclusions are observed with effort under 10X magnification, but can be characterised as minor
- Slight Included (SI1 and SI2) Inclusions are noticeable under 10X magnification
- Included I1,I2 and I3) Inclusions are obvious under 10X magnification with may affect transparency and brilliance
Lastly - colour. Many diamond colour distinctions are so subtle that you wouldn’t be able to tell from the naked eye. A pure and colourless diamond is considered to be of the highest quality and commands a higher price. The GIA have a system here too - the D-Z colour grading system. This system ranks stones from completely colourless (D) to light yellow (Z). Coloured diamonds such as yellow and pink aren’t included in this category and are graded separately.
What is the provenance of diamonds? Well, without lab testing it is impossible to prove where a diamond is from unless you know the maker etc - this trouble is often the case with antique diamonds. However we do know that up until the 1700s diamonds were sourced in Indian for about 2,500 years and were extremely rare. These diamonds would have been for the upper class. Between the 1700s and 1866 more diamond mines opened up, making them more accessible to the public. Places like Brazil and Latin America dominated the market with diamonds until more mines were found in South Africa in 1866. These South African mines were bought by De Beers and they restricted the supply of diamonds in order to keep demand up and the cost high. From then until 2002 diamond mining was heavily influenced by the civil war in Africa, producing what we call ‘blood diamonds or ‘conflict diamonds’. Nowadays diamonds can be sourced in Australia, Russia, Brazil, Botswana, Congo Republic and India just to name a few. Many of our own diamonds are antique which we have repurposed into a different setting.
Here are some facts on diamonds for the ending of our jewellery lesson.
Diamonds are between 1 billion and 3.5 billion years old!
The use of diamonds in engagement rings has been traced back to 1477 when Austrian Archduke proposed to Mary of Burgundy
They are April’s birthstone
The Ancient Greeks believed diamonds to be indestructible and have magical properties
Diamonds are the traditional gift for a 60th wedding anniversary
Diamonds feature heavily in our collection. We have a wide range of antique diamonds with their original setting, antique diamonds in a new setting and new diamonds! Across our collection diamonds come in many different shapes and sizes - if you have any questions about any of our items please contact us at firstname.lastname@example.org