Tavernier Blue
Specifications
| Weight | 115.16 carats* |
|---|---|
| Dimensions | 32.89 x 27.65 x 12.92 mm** |
| Color | Blue |
| Weight of Rough | Unknown; semi-cut crystal |
| Origin | Golconda, India |
| Date Found | c. 1610 |
| Current Location | Cut into the French Blue in 1671 |
*112 3/16 old carats
**Estimated from GemCad modeling.
Details
The Tavernier Blue Diamond: The Origin of the Legendary Hope
The Tavernier Blue Diamond stands as one of the most important and scientifically analysed gemstones in history. Its significance lies not only in its extraordinary beauty but also in its direct link to the French Blue and ultimately the Hope Diamond, one of the world’s most famous gems.
Much of the technical understanding of the Tavernier Blue was developed through research on the Hope Diamond itself. The stone was first documented by Jean-Baptiste Tavernier, the French gem merchant and traveller, who saw it around 1668. Tavernier described it as weighing 112 3/16 carats (Tavernier, 1676) and provided the only known drawing of the original diamond—an invaluable reference that allowed modern researchers to recreate its form centuries later.
Historical and Physical Characteristics
Redefining the Model
A major breakthrough in understanding the Tavernier Blue came with the discovery of a replica of the French Blue in January 2008 (Farges et al., 2008, 2009). Prior to this, all modelling of the Tavernier Blue relied solely on Tavernier’s historical drawing. The laser-scanned 3D data of the French Blue provided precise dimensions, allowing scientists to compare and refine the Tavernier Blue model.
Upon comparison, it became apparent that the newly modelled French Blue did not perfectly fit within the earlier Tavernier Blue model, despite historical evidence confirming that the French Blue was cut from it. Since the French Blue model was based on modern laser scanning, adjustments had to be made to the older Tavernier model.
Reconstruction and Gemmological Analysis
To resolve these discrepancies, researchers returned to Tavernier’s own words. In his 1682 account, he stated:
“If the stone is clean they do not do more than just touch it with the wheel above and below, and do not venture to give it any form, for fear of reducing the weight.”
This indicated that the Tavernier Blue was minimally polished rather than fully cut, meaning its facets closely followed the natural crystal faces of the original rough diamond. Using this insight, Scott created a hexoctahedral crystal model to determine facet angles and orientations. The French Blue model was then digitally nested within the reconstructed Tavernier Blue model, with each facet aligned according to the diamond’s natural crystal structure.
During the process, adjustments were necessary to accommodate cleavage planes—surfaces where a diamond naturally splits. Certain facets, including the upper and lower tables, had to be recut to avoid aligning with these cleavage directions. After refinements of 2–3°, the final model achieved an excellent match with Tavernier’s drawing while maintaining correct proportion and alignment.
The resulting reconstruction met all known historical and gemmological criteria:
- Weight within ±1% of the original (calculated 116.2 vs. 115.3 carats).
- The French Blue fits entirely within the Tavernier Blue model.
- 21 of 31 facets align precisely with natural crystal faces.
Scientific Significance
These correlations have profound implications. By identifying the orientation of the Tavernier Blue within its parent crystal, researchers can determine the exact location of cleavage planes and therefore infer whether additional “sister stones” could have resulted from the same rough diamond. The conclusion, published in Gems & Gemology (Sucher, Fall 2009), definitively resolved this long-debated mystery: no sister stones to the Hope Diamond exist.
A Digital Resurrection of a Lost Masterpiece
These computer generated images show the appearance of the Tavernier Blue diamond. A spectral file of the Hope diamond was imported to generate the exact color of the original diamond. Photoreal image generated using Diamcalc by Octonus (www.octonus.com)
Modern computer-generated images now reproduce the Tavernier Blue’s appearance with remarkable fidelity. Using the spectral data of the Hope Diamond, researchers recreated the precise hue of the original stone—an extraordinary deep blue with subtle greyish undertones.
Though the original Tavernier Blue no longer exists in its uncut form, its story continues through science, art, and digital modelling. As the ancestor of both the French Blue and the Hope Diamond, it remains a cornerstone of gemmological history—bridging 17th-century discovery with 21st-century technology.