How Our Pre-Auction Insights Revealed the True Value of This Blue Diamond

Description: 5.72 ct, Fancy Intense Blue, Cushion, VVS
High Auction Estimation: $1,398,602 pc
Price Realized: $1,539,336 pc
 GIA   Rarity   Diary
True Face-Up: Equivalent to that of a 9.15 carat which is ~59.9% larger than the average

Analysis: A Fancy Intense Blue Cushion brilliant-cut diamond, polished as a classic colorless diamond, probably manufactured during the 1960s or 1970s. The diamond’s Inner-Grade is very strong, and modifying its facet alignment could increase its saturation to Vivid. No significant gray Undertone is present in the color.

Quality Remark: Low Dispersion 

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Discover the IDU Grading Standard

Our pre-auction analysis leverages the IDU Grading Standard to evaluate fancy color diamonds, focusing on three key visual attributes not covered by GIA: Inner-Grade, Undertone, and Color Dispersion. These elements provide deeper insights into a diamond’s color intensity, hue influences, and color evenness—factors critical to its beauty and value. Additionally, our True Face-Up calibration reveals how a diamond’s carat weight translates to its visual presence.

Inner-Grade measures the saturation strength within the GIA-defined categories, determining the level of saturation.
Grade 1 places the saturation in doubt, indicating it borders on the saturation below.
Grade 2 is a weak saturation,
Grade 3 refers to a solid saturation,
Grade 4 borders on one saturation above. In the vivid category,
Grade 4+ is reserved for exceptional saturation.

Color Dispersion examines literally how well the color mosaic is dispersed across the diamond’s face-up view.
This aspect ranges from Grade 1, showing noticeable colorless areas, to Grade 4+, indicating perfect dispersion.

Undertone evaluates the subtle color influences within the diamond’s color, such as brightness or muted tones.
The undertone grade reflects the diamond’s color sensation and how well it meets our expectations of the color.
Grade 1 indicates a significant presence of another color.
Grade 2 indicates a mild foreign sensation.
Grade 3 indicates an insignificant undertone (most abundant).
Grade 4 is the pure form of the color.
Grade 4+ is reserved for pink diamonds where the undertone enhances the primary color, making it exceptionally desirable.

For an in-depth exploration of our grading methodology and how it enhances the valuation of fancy color diamonds, we invite you to read the full article.