Diamond – a bit of glam

Many people don’t realise that diamond is only made of one element. That element is carbon. This is the crystal structure of diamond.  It’s this arrangement of carbon atoms that determines how strong and glittery diamonds are.

This is 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 reality each side of this box would only be about 0.3 nanometers 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 it – the humble carbon atom.  Each of the black spheres you see represents a carbon atom.  However, how these atoms are arranged is very special and gives rise to the diamond’s remarkable properties.

As the structure lights up you can see that every one of the carbon atoms in the structure are attached to four other atoms.  This is a very strong attachment, and because each and every one of the atoms do this, this is what gives the diamond its tremendous strength.

Why is this crystal structure important?

Diamond is an incredibly important material, used in a range of settings from cutting with precision to aiding the development of new medicine.

Diamonds are rare commodities because they form at high pressures and temperatures  approximately 150 km 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 has the highest hardness and thermal conductivity of any bulk material. The hardness of diamonds is all thanks to its crystal structure.

Synthetic diamonds have long been in demand for industrial applications for tools. In the 1940s work began in earnest to try and develop a synthetic method of producing diamonds to replicate their superlative physical properties. In 1953 they succeeded and 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 eye.

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 diamond crystal structure has helped us to know much more about how all the materials in the world are composed.