Categories
Search


Advanced Search
 »  Home  »  Diamond Grading  »  GIA Excellent Cut Grade: Case Study  »  How AGS would grade these diamonds?
GIA Excellent Cut Grade: Case Study
by Garry Holloway | Published  14/03/2006 | Diamond Grading
How AGS would grade these diamonds?
The Lab Director of the American Gem Society diamond grading laboratory, Peter Yantzer, ran a Helium 3 Dimensional file through the AGS ASET grading software and concluded that the deep stone (C) rates as AGS 2 and (A) rates AGS 3 on a scale where 0 is best and 10 is worst.

Stone (A) received a cut grade of AGS 3 with deductions of:

  • 1.2 for contrast
  • Nil for leakage
  • Nil for face up brightness
  • 0.5 for face up dispersion
  • 1 for tilt (the girdle can be seen with about 58 of tilt)
  • Total 2.7 = cut grade of 3

Stone (B) received 0 for light performance. It has an extra facet or natural on the pavilion that would lower the symmetry grade – probably to AGS 1.

Stone (C) received these deductions using the AGS software:

  • 0.8 for contrast
  • 0.5 for face up leakage
  • 0.5 for face up brightness
  • 0.3 for face up dispersion
  • Total 2.1 = cut grade of 2
Article Series
Article Options
Popular Articles
  1. A review of the “foundation” of GIA’s new cut grade system
  2. USA Adventures June 2005
  3. The Diamond Industry in 2005
  4. AGS' new cut-grading of princesses: a first experience
  5. Why are there several dealers offering the exact same stone?
Popular Authors
  1. Garry Holloway
  2. Paul Slegers
  3. Neil Beaty
  4. David Atlas
  5. John Pollard