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Some every important changes have been made to the document. The grading system which they devised is comprehensive and requires some study to realize a workable understanding of the process. However, once you grasp the basic principles, you will wonder how anyone could buy a gemstone without using this kind of vocabulary. The following "walk through" of a 3.04 Burma sapphire grading report will help you understand the various components of the Prestige Gemstone Report.
| None | Insignificant | Faint | Moderate | Strong | Prominent |
| Extremely Rare | Very Rare | Rare | Uncommon | Common | Very Common |
AGL indicates the extent of enhancement using its ten category classification system.
| 1...2 | 3....4 | 5....6 | 7....8 | 9....10 |
| Excellent | Very Good | Good | Fair | Poor |
This section defines the stability of enhancements under normal wear and tear for the consumer.
| 1...2 | 3....4 | 5....6 | 7....8 | 9....10 |
| Excellent | Very Good | Good | Fair | Poor |
The color grade is simply based upon the purity of primary color. For example, the greener the emerald, the redder the ruby, or the bluer the sapphire, the lower the numerical grade on an AGL scale. The reason the 3.04 sapphire is a 3.5 in this sample is the fact the stone has 65% blue as its primary color. It is that simple. The less primary color, the higher the numerical color grade. For example, a 60% primary color would probably be graded a 4 color.
The color scan will generally break down into three perceived colors that total 100%. In the sample, the sapphire is 65% blue, 20% violet and 15% green. As a general rule, you will only see the first two colors or the stone will appear violetish blue. With the AGL Prestige Report, we are seeing changes compared to the older AGL colored grading system. Top grades are being pushed upwards. For example, in the old system, a 70% primary color or 3.5 color would probably be the best color grade you would receive. Also, in the past grading system, the top of the line 1.00 and 2.00 color grades were impossible to obtain and these grades were a theoretical standard. The new AGL grading system now allows for for 1.00 and 2.00 color grades.
| 0..5..15..20 | 25..30..35 | 40..45..50 | 55..60..65 | 70..75..80..85 | 90..95..100 |
| Very Light | Light | Light-Medium | Medium | Medium-Dark | Very Dark |
In the sample above the sapphire's tone is 75-80, or technically 77.5. Basically, tone describes the lightness or darkness of a gemstone. Color considered alone without taking into account the tone will lead to errors in interpretation. If a stone is too light in tone, the color will not be rich enough. Conversely, if a stone is too dark, it will sacrifice transparency and brilliancy.
| FI | LI1...LI2 | MI1...MI2 | HI1...HI2 | E1...E2...E3 |
| Free of Inclusions | Lightly Included | Moderately Included | Highly Included | Excessively Included |
Clarity is defined as the degree to which the stone is free of inclusions under 2.5x magnification. In the sample the clarity is LI2-MI1. Here is a good rule of thumb to remember: You will probably not see inclusions in a Lightly Included (LI) gem, you may see some inclusions in a Moderately Included (MI) gem, and you will probably see inclusions in a Highly Included (HI) gem. Excessively Included (E) gems have durability problems and should be avoided.
| 1...2 | 3...4 | 5...6 | 7...8 | 9...10 |
| Excellent | Very Good | Good | Fair | Poor |
The cutting of a gemstone numerically describes the proportions and geometry of a gem. The finish grade refers to the polish of a gem. In the sample the cutting grade is Good (5) and the finish is Very Good to Good (4-5). Unlike diamonds which are cut according to strict mathematical parameters, most colored gemstones are cut for weight retention.
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