CUT

Cut is the most important characteristics as it influence on a diamond’s sparkle. The diamond’s proportions symmetry and polish is the beauty of diamond. It extremely difficult to analyse as diamond cut has three primary effects on appearance which are:

  • Brilliance (brightness created by combination of all white light reflection from the surface and the inside of polished diamond)
  • Fire (dispersion of light into the colours of the visible spectrum and seen as flashes of colour)
  • Scintillation (flashes of light and dark, or sparkle)

 

When a diamond is cut from a rough stones, the cutter must balance appearance as to maintain as much carat weight from the rough stone as possible. The same rough stone can yield one of two potential diamonds which are:

  • A too deep cut diamond would yield a significant larger diamond and earning the diamond cutter a larger profit on investment.
  • A smaller or well-cut diamond may sell for less in total than the larger diamond but it will command a higher ‘price-per-carat’ not only because of its appearance therefore makes the diamond more expensive to create.

 

Grading Scale

Cut grade is assigned by the GIA (Gemological Institute of America) using the following scale to determine diamond grade:

    Excellent

    (Top 1%)

   Maximum fire and brilliance. Reflects nearly all of the light that enters the diamond, creating exceptional sparkle and life

   Very Good

    (Top 3%)    

   Properly reflects most of the light that enters the diamond producing superior fire and brilliance. Under normal lighting conditions appears very similar to Excellent Cut but for a lower price

       Good

   (Top 15%)

   Reflects a majority of the light that enters the diamond for an above average appearance. An excellent value compared to higher cut grades

        Fair

   (Top 25%)   

   Allow much of the light entering the diamond to escape from sides or bottom reduced perceived fire and brilliance. More acceptable in diamonds of less than 0.75 carats, where difference
   in sparkle are more difficult to perceive

       Poor

   (Top 35%)

   Allow much of the light entering the diamond to escape from sides or bottom. The diamond may appearance noticeably dull and lifeless, even to an untrained eye.

 

Cut Proportions

Diamond proportion refers to the relationship between the size, shape and angle of each facet of a diamond. Ultimately, diamond’s interaction with light which approximately 20% reflects off the surface while the 80% enters, a portion will escape through the bottom of the diamond. A well proportioned diamond will have each facet properly placed and angled as to maximise the amount of light that reflects back out of the crown of the diamond. This reflected light is perceived as scintillation, fire and brilliance.