Diamonds are graded from D to Z. Pure diamonds are actually clear, like glass. The highest quality diamonds contain no colour, which are called D colour. The colour grading of diamonds start with D so as not to confuse with so many other grading systems of ABC. After D comes E, and so on through to Z.

The differences between each colour is almost imperceptible, however, the difference between 2-3 colours is readily apparent (F to H). The most common colour of diamonds is a yellowish hue, caused by nitrogen trapped in the crystal structure of the carbon lattice. The further you go down the alphabet the diamond will appear to have a pasty yellow hue.

After Z the diamond is called a fancy coloured yellow diamond or a canary diamond, which is worth substantially more than a D! Other popular coloured diamond are almost priceless like pink diamonds and blue diamonds, which are caused by boron trapped inside the lattice structure.