Only a tiny proportion of diamonds are composed of pure carbon – known as Type IIA. These stones are incredibly sought after and valuable. All other diamonds contain varying degrees of nitrogen, which introduces yellow or brown tones to the stone. The GIA grades a diamond’s colour on a scale from D to Z, with D representing pure white, colourless stones, and Z representing yellow-hued stones. Diamonds graded D, E and F are considered colourless and are rarer than diamonds with a lower colour grade. Pragnell’s engagement rings feature diamonds that are graded from D to H. While barely noticeable to an untrained eye, a change of two or three colour grades has a huge impact on a stone’s value: being flexible with colour often means customers can buy a bigger stone for their budget. Furthermore, well-cut stones often appear whiter than their certificate might suggest. That’s why it is important to discuss the various options with an expert.