A diamond is a precious stone and is the hardest naturally occurring material known. It is made from carbon which can come in different forms depending on how its atoms are arranged. A diamond has a lattice structure in which the atoms are bonded together very strongly.
Diamonds are formed deep underground in the earth’s mantle, around a 100 miles down. They are formed under high pressure and temperatures and can take 1 to 3 billion years to form. They are brought closer to the surface by deep volcanic eruptions and are then mined by people.
For further reading and some fun facts on diamonds please click this link.
For a video explanation, please see below.