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Diamond Certificate Terms:
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AGS: American Gemological Society Laboratory (This lab grades cut) I think
that for the mose complete dataset that the AGS lab offers both the
seller and the buyer a great service, in that the data can complete
assure the most actively beautiful diamond possible, and the cut grade
and grading of the catagories makes it a snap to assure that the diamond
you purchase is the finest possible in the world!
AGS-000: Diamond rated by AGS, ideal polish, symmetry, and proportions, commonly called "Triple Zero Ideal".
Carat Weight, unit of measure for gems. One carat equals 200 milligrams, or 1/5th of a gram.
Clarity: The clarity grade of the diamond listed.
Color: The color grade of a diamond is rated from "D", the most pure lacking of color, to "Z".
Crown: The angled area of a diamond extending from the girdle to the table.
Culet: Culet (bottom point of diamond), described as, None or Pointed, Very Small, Small(most desired up to this point), Medium and Large.
Cut: Refers to a diamond shape and cutting style, as well as proportions rated by the gem labs.
Comments: A gem labs additional comments regarding identifiable traits of a diamond not outlined on the plot, or diagram, of that diamond.
Ideal Cut: This term describes a diamond conforming to the AGS "Ideal" cut standards, or GIA "Excellent" rated cut.
Depth: Total Depth measurement in percent from the table to the culet, in relation to the overall diameter measurement.
EGL: European Gemological Laboratory. EGL has laboratories in the United States as well as Israel, Europe, India, and other countries.
Finish: Refers to polish and symmetry descriptions.
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Excellent: As cert description indicates
exceptional attention to detail (Gia's highest rating, AGS's second
highest
Very Good: This term is going to basically describe the catagory as very fine attention to detail, and frankly at this point I find personally sheer perfection...
Good: Good on a GIA or AGS certificate is the benchmark of appearant perfection and no denegrating features in that catagory what so ever, in the "Good" range is where your dream diamond lives for most, past that is sort of a lab rat's premium... {Grin}...avoid grades of "Fair" or "Poor".
Fluorescence: The tendancy to "Glow" when exposed to UV light, described as...Inert or None, Faint, Medium, Strong, and Very Strong
Here's an article by the President of the GIA you might find interesting, but basically this is a non-event and should not rule out a fine diamond
GIA: Gemological Institute of America - Gem Trade Laboratory, now also gives cut ratings for round diamonds, from "Poor" to "Excellent" being ideal.
Girdle: The intersection of the crown and pavilion which defines the perimeter of the diamond, sub-letters (p) Polished, (f) Faceted.
Girdle edge can be laser inscribed with a Diamond Grading Report number, or even personal messge.
- Girdle descriptions are listed as:
XT: Extremely Thin
VT: Very Thin
T: Thin
Med: Medium
SLK: Slightly Thick.
TK: Thick.
VTK: Very Thick.
XTK: Extremely Thick.
*Most Desirable is Medium, or not more than two steps
Pavilion: Lower half of the diamond, extending from the girdle to the culet.
Plot: The map of the activity in the diamond, or "fingerprint", but done more as an exaggerated roadmap for the next grader or gemologist to verify the diamond.
Premium: This term can also be associated with the AGS grade (1) in any given catagory, and this is also a great place to get all the dramatic beauty of the finer cuts, even if outside the range for ideal by just a whisker... No denegration in this description, guaranteed!
Sarin: Computerized Proportions Analysis to determine the proportions of the diamonds that they grade.
Shape and Cutting Style: The shape of the diamond. Though a huge number of cut styles exist, the most general cut shape types include... Round Brilliant, Radiant Cut, Princess Cut, Pear Shape Cut, Oval Cut, Marquise Cut, Emerald Cut, & Trillion Cut.
Measurements: The millimeter measurement across the diamond, the widest and narrowest are listed in the round, then depth. Diamond rounds are described with three measurements, the widest and narrowest diameter and the depth, in that order. For fancy shapes be sure and do the math too, the aspect ratio is critical to the look of a great diamond in the fancy shapes. Take the marquise for example, which si best at a 2:1 aspect ration, or twice as long as it is wide. The oval is best in the 1.5:1 ration, as is the pearshape and the emerald cut. You will find a range for cool in fancy shapes, just call to discuss any in depth questions you might have further.
Table: The large facet on the top of the diamond, refered to as a percentage of the diameter of the measurements. In a round diamond this range for the table is listed in my "What is an ideal cut?" page in depth.
Weight: The carat weight of the diamond graded in the lab report.( 1 Carat = 200 milligrams. )
