What Is Diamond Polish?

The polish of the stone is a very important character in determining the overall brilliance of the diamond. It determines how well light is able to pass through the diamond. The stones with poor polish will display microscopic polish lines that can blur the surface of the stone affecting the light entering and exiting the diamond. Therefore, it is always wise to pick laboratory certified diamonds to ensure good, very good or excellent polish. One of the major reasons behind poor polish is because the diamond cutters who handles the diamond try to reduce their cost by not spending enough time polishing the stone.

How Is Polish Graded?

The GIA has established the diamond polish grade similar to the way Symmetry is graded. According to the GIA, these grades range from Excellent to Poor based on the presence of polish features at 10x magnification.

  • EX or E - Excellent, Flawless at 10X magnification
  • VG or VGD - Very Good, Extremely difficult to locate under 10X magnification
  • GD, GO, G - Good, Very difficult to see under 10X magnification
  • F, FR, FA - Fair, Noticeable under 10X magnification
  • PR, PO, P - Poor, Easy to notice under 10x magnification/Visible to the unaided eye
  • VP, VE - Very Poor, relatively easy to notice with the unaided eye
  • EX or EP - Extremely Poor, Obvious to see with the unaided eye

The difference between these grades may be little to an unaided eye. Normally, these differences will be visible only under magnification. Therefore, a diamond with a polish rating of Good can still be a very valuable stone. However, those stones with grades Fair (FR) and Poor (PR) indicate that the flaws can still be visible to an unaided eye thus affecting the beauty of the stone.

Mass production of rings with poor quality control can result in porosity or rough spots in the metal. Porosity is those little surface holes on the ring that worsens as it goes deeper in the metal. Porosity can make your ring weak thus breaking it down eventually.


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