A diamond is a precious stone. Just like coal, it consists of carbon. However, diamonds are far more expensive than coal because they are very rare.
Diamonds are found in the earth. They are often found mixed with other substances. Depending on which substance they are mixed with, they have a different colour. This is why there are green, pink, blue or yellow diamonds. However, a diamond made of pure carbon is transparent. Because they are so valuable and sparkle, diamonds are often used as jewellery.
Diamonds are usually octahedrons, so they have eight sides. However, twelve-sided, four-sided or cube-shaped, i.e. six-sided, diamonds have also been found. When diamonds are extracted from underground mines, they are usually still very rough, misshapen and opaque. These finds are called rough diamonds. Diamonds are only really valuable once they have been cut. This is done by so-called diamond cutters, whose job it is to cut rough diamonds. In polished form, diamonds are smooth and transparent.
Diamonds are also the hardest material known in the world. That’s why you can cut or smash very hard things with a diamond. For example, you can cut a glass bottle open lengthways. Even the drill bits used to drill for oil often have a diamond tip.