Mirror of Portugal
Specifications
| Weight | 26.07 carats |
|---|---|
| Dimensions | 17.89 x 16.73 x 10.98 mm |
| Color | Colorless |
| Weight of Rough | Unknown |
| Origin | Golconda, India |
| Date Found | Unknown |
| Current Location | Recut into Mazarin III, stolen 1792 |
Details
The Mirror of Portugal (also known as Miroir du Portugal, or MdP) is one of the more enigmatic historic diamonds. Despite having passed through the hands of royalty — including the monarchs of Spain, England, and France — remarkably little concrete information exists about the stone. It appears in a handful of royal portraits and crude line drawings, which indicate it was a large table-cut diamond.
Historical records suggest that the MdP was pawned multiple times and eventually recut into the Mazarin 3 in the late 17th century. Its trail was believed to have ended during the theft of the French Crown Jewels in 1792, when it disappeared without a trace — or so it was thought.
Photo by Francois Farges, ©2009
That narrative changed significantly with the discovery of a lead model found alongside the well-known lead replica of the French Blue. This newly found model is square in shape and corresponds to a diamond of approximately 26 metric carats, closely matching the description found in the 1691 inventory of the French Crown Jewels (as published by Brisson in 1787). That record described the MdP as weighing 25 3/8 old carats, or 26.07 metric carats, and specifically identified it as a square table cut.
The existence of this lead model, which likely predates the recutting of the stone into the Mazarin 3, suggests it may be a true physical representation of the Mirror of Portugal’s original form. If so, the model would be over 300 years old, offering a rare and valuable reference point for historical gemological reconstruction.
Using photogrammetry techniques (outlined in Sucher, 2008), a precise GemCad model was developed from the lead cast, leading to the creation of a cubic zirconia (CZ) replica. Although the design appears visually simple — a classic step-cut arrangement — its optical performance is quite striking. When viewed face-up, the mirror-like symmetry and parallel facet rows create a recursive reflection pattern, often referred to as a “house of mirrors” effect. This optical illusion gives the impression of infinite depth, making the stone appear several feet deep from a frontal perspective.
Photoreal image generated using Diamcalc by Octonus (www.octonus.com)
The Mirror of Portugal replica thus reveals the exceptional skill of early diamond cutters. While not conforming to modern brilliance standards, the original design demonstrates a deep understanding of reflective geometry — emphasizing visual depth and light play over sheer sparkle.