When choosing a diamond, you should also consider other attributes that affect quality and price, such as polish, which is evidence of how well it has been cut, finished and cleaned, and symmetry, which describes the exact shape and arrangement of its facets. You should also consider the depth percentage of a diamond, which is the ratio of the diamond’s diameter to its depth. Each shape has different ranges of ratios that are considered ideal. Finally, look at the length-to-width ratio, which determines how close to perfection is the diamond’s particular shape. It is also important to understand the various laboratories that grade and certify diamonds. Along with the 4C’s, if you wish to make the best purchase, all of these factors need to be considered.