As you know, a rough diamond crystal is cut and polished on a wheel (known as a ‘scaife’) to make facets. These facets in turn act as windows and allow light to enter the diamond and bring out the coveted brilliance, dispersion and scintillation that diamond-lovers look for. (Confused by these terms? Check out our Glossary to clear things up.)
Facets allow the light to enter the diamond, but also allow the light to reflect back from inside the gem. The polishing process can even further enhance the combined external and internal reflection.
Diamond Rough
Polishing a Diamond
When evaluating the polish of a diamond for grading, many characteristics are taken into account, including features such as: Abrasion, Lizard Skin, Nick, Pit, Scratch, Burn Marks and Naturals. But mainly, the polish of a diamond is based on the presence of ‘Polish Lines’. Polish lines are the most common polishing variation found, and appear as transparent bumps present on the surface of a facet as a result of improper polishing. Presence of polish lines and other polishing variations have a direct effect on the scintillation of the diamond. According to the GIA, the highest cut grade of Excellent is possible in a diamond only when the polish grade of a diamond is either ‘excellent’ or ‘very good’.
What does an ‘excellent’ polish grade mean?
An excellent polish rating indicates that utmost care has gone into manufacturing the diamond to increase the scintillation, or reflectivity of its facets. Given a choice, you should go for excellent polish in your diamond.
How does polish affect diamond price?
As is true with other parameters, an excellent polish grade is what you should aim at. Although this will be more expensive, it ensures that you are getting the biggest, visually noticeable advantage in your diamond.
