Our pre-auction analyses focus on visual elements that are not expressed on the GIA report, such as “inner-grade”, “undertone” and “color dispersion”. We use grades 1, 2, 3, 4 and 4+ to evaluate these features. It is often difficult to identify these characteristics when viewing stones in an auction catalogue. For the first time, we are also including the rarity of each stone, calculated by our Rarity Evaluator tool.
Please note that all photos were taken with an iPhone 6.
In many of the lot descriptions, Christie’s noted that the stones’ weight is ‘approximate’; we questioned why this was specified because with a GIA report, the weight is always stated as an exact measurement.
Lot 242: The Oppenheimer Blue, 14.62 carats; FCRF Rarity Evaluator: A stone with similar characteristics is available in the market only once every few years. Approximately 23% of Blue stones are cut as Emeralds.
High Estimate, Price Per Carat: $3,170,446
Realized Price (Including Premium): $3,967,351 Price Per Carat (Updated 20/5/16)
It is very rare to see a diamond with a 1:54 ratio and low depth percentage of 59.9% (which is a feature, as low depth makes the diamond appear larger than its actual size). The color is very dark and could easily be mistaken...