Pre-Auction Analysis: December 10th 2019, Sotheby’s New-York, Magnificent Jewels

Our Sotheby’s, New-York Pre-Auction Analysis focuses on elements that are hidden from the unprofessional 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 (UDI; a detailed explanation appears at the bottom of this article). When we analyze and grade any Fancy Color Diamond it is always done in relation to its GIA grade.

We use grades 1, 2, 3, and 4, 1 being the lowest grade. Grade + is granted in rare cases and stands for stones with an exceptional characteristic. Stones that receive a minimum total UDI score of 8, without a red remark, are considered to be “Gems” and are generally sought after by high-end jewelry brands, collectors and the investment community.

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

• All images in this article review were taken with an iPhone 11pro, no filters were applied.
• All auction valuations are per carat and in US Dollars.

Lot # 423

7.00 carat Fancy Blue, Pear, VS2. High catalog estimation: $400,000‬ per carat

Market Prevalence: A similar diamond enters the market once every 3 – 5 years

Result: Didn’t reach the minimum

A relatively large, fancy blue, pear shape diamond. The color dispersion is poor, mainly visible at the tip and at the rounded base of the shape. The gray undertone is not very noticable and the inner-grade is low. 

Total Visual Score: 7 out of 12

To review the GIA Report Click here -> 10733869

Lot # 500

7.55 carat Fancy Deep Grayish Blue, Cushion, SI2. ‘THE INDIAN BLUE’. High catalog estimation: $1,059,602 per carat

Price realized: $ 879,788 pc

An impressive, old mine-cut, blue diamond, with a gray modifier. The stone’s color is situated on the axis between black and “Ink-blue”. In fact, it is extremely dark and could have been easily graded