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;a detailed explanation appears below). We use grades 1, 2, 3, and 4 (1 being 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. A detailed explanation on our grading system is at the bottom of this article.

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

All images in this article review were taken with an iPhone 7 – no filters were applied.

All auction valuations are per carat and in US Dollars.


Lot #1776

14.18 carat fancy blue step-cut, VVS2

High catalog estimation: $540,931 per carat

Not sold

A rare and important size and shape for any blue diamond, however in spite of the closed mounting on the back and the pink halo, the overall “blue experience” is quite saddled, especially due to the low color dispersion on the face up....