Pre-Auction Analysis: Sotheby’s Hong Kong, December 17th, 2024

Our pre-auction articles guide professionals in making informed decisions. Retailers benefit by understanding the reasons behind price differences between the color diamonds they showcase and pre-owned jewelry on the open market, while also recognizing quality variations. These articles also assist dealers seeking to purchase color diamonds without attending the preview.

The IDU grading system for color diamonds is straightforward and accessible to all. It assesses three visual attributes not covered in the GIA report: Inner-Grade (richness of color within a defined saturation), Dispersion (how well color is distributed across the face-up view), and Undertone (the color sensation relative to the color as most people imagine it). For those interested in learning more, a brief explanation of the IDU grading is available at the end of this review. For a detailed overview, check out this link.

The grading and analysis are conducted by trained FCRF experts who travel to all major auctions. Some lots are analyzed by manufacturers or dealers within the industry after ensuring they have no vested interest in them. To maintain objectivity, we often cross-reference several analyses across multiple experts.

Our experts use the latest iPhone models to capture images of the diamonds during the auction preview. Ensuring that they appear under the same lighting conditions as seen by other viewers. No filters or corrections are applied to the images.