The article concludes with photos and proportion data of 15 stones given as examples of 5 Categories of cut quality. The Categories are presented as the ‘foundation’ of an eventual grading system, but a vague qualification is added; they may not be the basis of the final grades. It seems their foundation is incomplete which means that this analysis of it must also be incomplete.
 
In this review we will examine each of these stones using various tools designed and / or used every day by the author. There are advantages to reading on-line because there are several links included. However you may find having a printed copy at hand will improve comprehension, and be convenient for comparing images and discussions.
 
HCA proportions were chosen to cover the most widely available diamonds. The colored part of the chart shown below shows the pavilion on the vertical chart scale with a larger scale (39.5°-43°) because it is the proportion factor with the greatest impact on diamond appearance. The horizontal axis represents crown angle (28°-40°). The third most important variable, table size, is represented on 13 different charts ranging from 53% to 65%. In hind sight, it appears diamonds with shallower crowns and pavilions may become more common in the future.
 
In the chart shown here, an interpretation is made of some ranges of proportions given by the GIA based on my assumption that the GIA would concur with previous work done by MSU, Bruce Harding and Jasper Paulsen’s re-interpreted Tolkowsky calculations. But it should be noted that three of the 15 example stones fall outside these oval predictions.
 
The accuracy of the scanning devices used at the time of the GIA studies has resulted in significant rounding of table, crown and pavilion data. Pavilion lower girdle half facet length and crown star half facets length are quoted in 5% steps. All the proportions are considered as averages; angular deviations within the facet grouping for each measured parameter will be downgrade for diamonds with symmetry grades below Very Good. This approach is, in my opinion, less than perfect. 
 

This HCA 55% table chart (extend to include some additional GIA proportions) has black ovals representing our interpretation of ranges of crown and pavilion angles for categories 1, 2 and 3 mentioned in the article. In white is the new AGS 0 ‘candidates’ proportions for 55% table. The black numbers represent the crown and pavilion (only) coordinates for each of the 15 stones in the 5 categories (except 4.3).

 
Where additional specifications are shown in the charts below (next pages), it is because there was a difference between the relevant data quoted in the 2001 Fire article. The earlier information was not rounded as broadly as that in the Foundation article.