A P R I L

DIAMOND

Diamond is the hardest mineral on Earth, and this, combined with its exceptional lustre and brilliant fire, has made it the most highly prized of all gems. Pure, colourless diamond is the most popular, but other varieties – from yellow and brown to green, blue, pink, red, grey, and black – are also found, depending on the impurities present. Because of the uniform arrangement of their constituent carbon atoms, diamond crystals are well-formed – usually octahedral with rounded edges and slightly eonvex faces. Their perfect cleavage facilitates the early stages of fashioning, but they can only be polished by other diamonds.