Many people don’t realise that a diamond is only made up of one element. That element is carbon.
You are looking at a scale model of the smallest building blocks of one of the most precious gems known to man.
What’s the scale of this model?
The atoms are contained in a box that is 1 metre by 1 metre by 1 metre. In real life, each side of this box would only be about 0.3 nanometres in length. If you are lucky enough to have a diamond ring on your finger, that gem will contain billions of these boxes of atoms stacked up together.
Like molybdenum, this structure only has one type of element. In this case, it is the humble carbon atom. Each of the black spheres you see represents one carbon atom. However, the way these atoms are arranged is very special and gives rise to the diamond’s remarkable properties, such as its strength and sparkle.
As the structure lights up, you can see that every one of the carbon atoms in the structure are attached to four other atoms. As you can see, this is a very strong attachment and is the reason for the diamond’s tremendous strength.
The fact that carbon can bond with four other elements at a time makes it such a useful element. There’s also a lot of it. It is the fourth most abundant element after hydrogen, helium and oxygen.
The stable carbon to carbon bonds form the backbone of organic chemistry makes up much of the ‘stuff’ in our environment. Key to this is the carbon cycle where the building blocks of trees, vast complex molecular materials, such as lignin and cellulose, are made from the carbon in our atmosphere.
Why is this crystal structure important?
Diamond is an incredibly important material, used in a range of settings from cutting with precision to aiding in the development of a new medicine.
Diamonds are rare commodities because they form at high pressures and temperatures approximately 150 kilometres below the surface of the Earth. They are brought close to the surface by deep volcanic eruptions.
Diamond comes from the Greek word for ‘unbreakable’, an appropriate description of its extreme hardness. Indeed, diamond scores the highest in hardness and thermal conductivity of any bulk material. The hardness of diamonds is all thanks to that special crystal structure we mentioned earlier.
Synthetic diamonds have long been in demand for industrial applications and tools. In the 1940s work began in earnest to try and develop a synthetic method of producing diamonds to replicate their superlative physical properties.
Success came in 1953 when the first reproducible synthesis was designed. This synthesis can produce both industrial grade diamonds and gem-quality diamonds. In some cases, not even a gem expert can tell the difference between a natural and synthetic diamond by sight.
Why is the structure important to Australia?
Diamond was one of the first crystal structures to be discovered. The structure was discovered by none other than father and son team, William Henry and William Lawrence Bragg, who both had very strong connections to Australia. Learn more about them here.
The historical understanding that has come about as a result of understanding the crystal structure of diamond has helped us to know so much more about how all the materials in the world are composed.