Diamond is a crystal made of a single element: pure carbon. It is the bonds between its atoms that make it a unique gemstone with many qualities. It is known for its extreme hardness, obtaining the maximum score of 10 on the Mohs scale (measurement of the hardness of minerals).
Diamond is the hardest substance there is and nothing can scratch it except another diamond. This is the reason why diamond is not only used in jewelry, but also in industry, because it has the ability to scratch or cut any other material. Only prolonged heat above 600°C can cause a diamond to burn.
The price of a diamond is established according to four main criteria, called the 4 Cs: Carat (weight), Color (color), Clarity (purity) and Cut (size/shape).