Firstly you need to understand the four characteristics used to grade a diamonds quality. These are – cut, colour, clarity and carat weight. All known as the Four Cs of a diamond. So you should select the four different grades depending on what aspect is important to you and more importantly how much you want to spend. Cut - Refers to the style or design guide used when internally shaping a diamond with proportions and symmetry. The most common two cuts are brilliant cut or step cut. The cut determiners how brilliant the diamond is and how much light reflection it has. Colour- for white diamonds colour is graded by its clearness, so the lack of colour the better. D is the highest colour grade, and we recommend J as the lowest colour grade to opt for. Clarity - when referring to clarity we are talking about the amount of blemishes the diamond has externally or inclusions internally. With most diamond marks will only be seen under magnification and if a diamond is completely flawless it is graded F, or IF for internally flawless. The image below shows the different diamond clarity grades and the red marks resemble inclusions, which are only visible through magnification. Diamond Carat Weight - The carat weight of a diamond refers to the diamonds weight and not the size of a diamond. 1 carat is equal to 200 milligrams and is further divided into points where one point is equal to 0.01 carat. A half carat diamond is 0.50 points and a three quarter carat diamond is 0.75 points. This chart below shows the different sizes of diamonds at different carat weights. The next step is to choose the diamond shape you want. There are nine most common diamond shapes. These shapes are round brilliant cut, princess cut, oval shaped, marquise cut, pear shaped, cushion cut, emerald cut, heart shaped and Asscher cut. All of these diamond shapes can be combined with any style of ring setting and precious metal type.