This pre-auction analysis will focus on visual elements and other observations that are not expressed on the GIA report nor in the catalog. Our analysis expresses characteristics such as Undertone, Color Dispersion, and Inner-Grade (UDI). We use grades 1, 2, 3, and 4 (grade 1 is the lowest grade).

The grade 4+ is granted in rare cases and stands for an exceptional characteristic. Stones that receive a total UDI score of 8 or above (SI1 or better) are considered to be gems and are probably suitable for high-end jewelry, collectors, and the investment community.

For your convenience we added the direct links for the GIA reports and for the FCRF Rarity reports.

All images in this article review were taken with an iPhone 7.

All auction valuations are per carat and in US Dollars.

 

Lot # 2032

9.05 carats fancy vivid yellow Emerald cut, VVS1

High catalog estimation: $ 213,255 per carat

Price Realized: $179,750 per carat

As we mentioned in the opening very few fancy color diamonds carry an outstanding characteristic that entitles them to a  grade of 4+, even fewer of these stones are accompanied by other supporting high grades. This vivid yellow emerald cut diamond has a rare yellow undertone with a delicate touch of orange and receives a grade of 4+.

The inner-grade has the highest rating for a yellow stone and receives a grade 4+ as well.

Low color dispersion is inherent in emerald cut diamonds especially when they are rectangular. In this case, the color dispersion is above average and receives a grade of 3.

Total quality score: 11++    

 

 

Lot # 2077 A

14.93 carats fancy vivid pink oval, VVS1

High catalog estimation: $ 2,757,289 per carat

Price Realized: $2,143,555 per carat

Auction houses will often  mention that their pink fancy color diamonds have a Type IIa report as if it is positive characteristic. However, most Type IIa pinks are hazy and lean towards the warm undertone of the pink spectrum (*To read the FCRF article “Not My ‘Type’: Common Misconceptions About Type IIa Pink Diamonds”: Click here).

This vivid pink has some colorless patches around the crown and receives a grade of 3.

The inner grade is a bit lower than the average vivid pink and receives a grade of 2.

The pink undertone is situated in the middle of the pink spectrum and receives a grade of 3.   

Total quality score: 8    


To review the GIA Reports Click here

To review the FCRF Rarity Report Click here

 

Lot # 2088

5.39 Carat fancy purplish pink pear, IF

High catalog estimation: $ 429,675 per carat

Price Realized: $344,583 per carat

The undertone of this pink pear shape has a subtle purple influence and receives a grade of 3. The inner-grade is quite weak with a grade of 2 and the color dispersion is average with some colorless patches with a grade of 3.

Total quality score: 8    

To review the GIA Reports Click here

To review the FCRF Rarity Report Click here

 

Lot # 2090

8,80 carats fancy intense pink step cut diamond, VVS1

High estimation: $1,096,568 per carat

Price Realized: $1,098,590 per carat

A subtle change in the angles of the four corners of the pavilion changed the appearance of this stone from “emerald cut” to a modified step cut diamond. The fact that this pink diamond doesn’t have nitrogen in its crystal (type IIa) does not  indicate  any special advantage. The Inner-Grade is quite strong and receives a grade of 3. The hue has a slight orange undertone, as is common for most Type IIa pink diamonds; although in this case its undertone seems pitchy and receives a  grade of 3. Most of the color is situated in the large four corners of the pavilion while the center has very little color, as this is a typical characteristic of fancy color step cut diamonds it receives a grade of 3.   

Total quality score: 9      

To review the GIA Report Click here

To review the FCRF Rarity Report Click here


General

We use 1, 2, 3, 4, and 4+ to grade the three visual elements that GIA is silent about, that, however, impact value dramatically.

Inner-Grade refers to the strength of color within each GIA saturation category:

Grade 1 weakest, bordering the saturation below.

Grade 2 weak (most abounded).

Grade 3 full-bodied color (above average).

Grade 4 very strong saturation.

Grade 4+ applies for the vivid category only, exhibiting the strongest possible saturation (rarely seen).

Undertone refers to a subtle hue influence in the body color of the stone. For example:

A fancy blue diamond with a significant gray presence in its general appearance will be graded with a low undertone grade of 1. A fancy blue that has no gray influence and will be close to a primary blue will receive the grade 4.

In a pink fancy color diamond, a stone with a warm undertone (such as orange or brown) will receive a low undertone grade. A pink stone with a cold undertone (such as purple) will receive a high grade.

In yellow fancy color diamonds, low foreign influence or a light orange influence will grant the stone a high undertone grade. When the yellow undertone looks like a true primary yellow, it will receive the rare grade 4+. Green and brown undertones will grant a low grade in the yellow category.

Color Dispersion relates to how well the color is dispersed in the face-up view of a fancy color diamond, regardless whether the GIA grades the stone as even. A stone with many colorless areas will receive the grade 1, while a stone that exhibits its face-up view with no colorless patches will receive the grade 4+. Unlike the first two elements, color dispersion is not a gemological quality and has only to do with cutter proficiency.