Pre-Auction Analysis: November 27th, 2021, PHILLIPS Hong Kong

This is our first Phillips Pre-Auction Analysis, and we hope you find it useful. Due to COVID restrictions, Hong-Kong is still closed to visitors. This Auction Analysis could help those who would like to bid in the upcoming Phillips auction without physically inspecting the goods.                                                 

Our Phillips Hong Kong Pre-Auction Analysis focuses on elements that aren’t visible to the untrained eye. We will describe the important visual elements for those who cannot attend the preview and discuss characteristics such as: Undertone, Color Dispersion, and Inner-Grade. These factors, collectively termed UDI, are explained in detail at the bottom of this article. We analyze and grade Fancy Color Diamonds relative to their GIA grade.

We use grades 1, 2, 3, and 4, with 1 being the lowest grade. Grade “4+” is granted in rare cases and denotes stones with exceptional characteristics. Stones that receive a minimum total UDI score of 8, without a red remark, pass the industry threshold and can be traded easily. Fancy Color Diamonds that are graded 10 or above, (without a quality remark) are usually sought after by high-end jewelry brands, collectors, and the investment community.

For your convenience, we have added direct links to the GIA reports.

• All images in this article review were taken with an iPhone 12 Pro; no filters were applied.
• All auction valuations are per-carat and listed in US Dollars.

Lot: 545

Description: 3.03 ct, Fancy Vivid Yellow, Emerald cut, VS1

High Auction Estimation: $46,204 pc

Didn’t reach the minimum

Rarity: A small number of similar diamonds enter the market yearly… Check Rarity Here 

GIA Report: View

Analysis: A Vivid Yellow rectangular Emerald cut, featuring the highest possible inner grade in the yellow palette. A soft, Orange undertone is present in the hue, giving the diamond a pleasant appearance. The stone was cut as a traditional Emerald cut, without modifying the angles to reinforce saturation or color dispersion.

Visual Assets:

Total Visual Score 12 out of 12

Lot: 580

Description: 5.03 ct, Fancy Intense Greenish Yellow, Pear, VS2

High Auction Estimation: $71,570 pc 

Price Realized: $59,179 pc

GIA Report: View

Analysis: A relatively large diamond with a Green and Yellow color combination. According to the GIA report, the diamond’s color is composed of ~15% Green and ~75% Yellow. This color combination can be seen in several appearances, depending on the origin of the stone and the type and amount of the fluorescent. In this case, the fluorescent is Green and the level is Strong. In cases where the fluorescent color corresponds with the stone’s color, it will reinforce the diamond’s color with a matching glow under sunlight (or light waves that imitate sunlight) and will produce an edgy, “radioactive” look that will entail a price premium. The second image shows the stone in its glowing state.

When a stone is subjected to sharp color changes following its exposure to different light sources, we tend to avoid grading the undertone as the grade can be misinterpreted.

Visual Assets:

Total Visual Score N/A

Lot: 586

Description: 9.25 ct, Fancy Vivid Yellow, Radiant cut, IF

High Auction Estimation: $48,648 pc

Price Realized: $32,180 pc

Rarity: An extremely small number of similar diamonds enter the market yearly… Check Rarity Here

GIA Report: View

Analysis: A 9.25 carat Vivid Yellow Radiant cut diamond with a low inner-grade. Some colorless patches are seen on the crown and no significant Green or Brown undertone is present in the Yellow hue. Depth is 63%, which makes the stone look a bit larger from the face up, relative to its weight. The clarity of the GIA report states that the diamond is Internally Flawless. However, considering that the GIA report is dated January 2010, buyers must take into consideration that the diamond’s clarity may have been jeopardized over the past 11 years.

Visual Assets:

Total Visual Score 9 out of 12

Lot: 587

Description: 5.05 ct, Fancy Pink-Purple, Radiant, VS1

High Auction Estimation: $404,040 pc

Withdrawn from auction

GIA Report for 5.05 ct: View

Analysis: According to the GIA report, the diamond’s color is composed of ~40% Pink and ~60% Purple. The crown area is almost colorless, as are some parts of the table. A subtle Gray undertone is seen in the hue under a warm light, a common appearance in diamonds with a Purple body color, and could also indicate the geographic origin of the stone. The top of the diamond was planned as a step cut while the pavilion was polished with the traditional Starburst cut. Therefore, the GIA defined the cut as a Mixed Cut.

Visual Assets:

Total Visual Score 7 out of 12

General

We use 1, 2, 3, 4, and 4+ to grade the three visual elements that GIA is silent about, although they impact the 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 common).

Grade 3 full-bodied color (above average).

Grade 4 very strong saturation.

Grade 4+ applies to 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 that is 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 as to 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, the color dispersion is not a gemological quality and is the result of cutter proficiency.