The Florentine Diamond is one of the most celebrated and most lamented of all the great historic diamonds: a pale yellow stone of 137.27 carats, cut in an unusual double rose form bearing 126 facets, and for centuries one of the supreme ornaments of European royal regalia. Known also as the Tuscany Diamond, and at various points in its long career as the Grand Duke of Tuscany or simply the Austrian Yellow Diamond, it passed through the hands of the Medici, the House of Habsburg-Lorraine, and the Austrian imperial treasury before vanishing in the chaos that followed the collapse of the Austro-Hungarian Empire at the end of the First World War. Its present whereabouts are unknown. No credible sighting has been confirmed in over a century, and the Florentine occupies a singular place in the canon of lost diamonds — a stone whose documented history is rich and whose disappearance is all the more tantalising for being so recent in geological and even human terms.

Physical Character and Cut

The Florentine's recorded weight of 137.27 carats places it among the largest diamonds ever to have entered European royal collections. Its colour is described consistently in historical sources as a pale, somewhat greenish yellow — a hue that in modern gemmological terminology would likely fall within the Fancy Yellow to Fancy Greenish Yellow range, though no laboratory grading report has ever been issued for the stone. The colour is not the saturated canary of the finest fancy yellows but rather a cooler, more complex tone that contemporaries sometimes described as straw-coloured or citrine-like.

What makes the Florentine especially remarkable from a lapidary standpoint is its cut. It is a double rose cut — a form in which both the upper and lower surfaces of the stone are covered with triangular facets rising to a central point, producing a lens-shaped outline with no flat table and no pavilion in the modern sense. The Florentine's version of this form is exceptionally elaborate, with 126 facets arranged in nine-sided (nonagonal) symmetry. This nine-sided outline is itself highly unusual; most rose-cut diamonds are fashioned to circular, oval, or pear-shaped outlines. The nonagonal form has been cited as evidence that the cutter worked around inclusions or irregular crystal geometry, though the precise internal clarity of the stone is not documented in any surviving technical record. The double rose cut was already an archaic form by the seventeenth century, suggesting the stone was cut no later than the early 1600s and possibly earlier, during the high period of Indian diamond fashioning or early European lapidary work.

Origins and Early Provenance

The Florentine's origins before the seventeenth century are obscure and have attracted considerable mythologising. One persistent tradition holds that the stone was once owned by Charles the Bold, Duke of Burgundy, and was lost at the Battle of Grandson in 1476, subsequently passing through Swiss and Portuguese hands before reaching Florence. This narrative is colourful but difficult to substantiate; the diamond attributed to Charles the Bold in contemporary accounts was described differently in weight and colour, and the chain of custody between 1476 and the stone's secure appearance in Medici inventories has never been convincingly documented. Gemmological historians treat the Burgundian connection with scepticism.

What is firmly established is that by the early seventeenth century the Florentine was in the possession of the Medici grand dukes of Tuscany. It appears in the inventory of Ferdinando I de' Medici (1549–1609) and is described in detail by the Flemish gem merchant and traveller Jean-Baptiste Tavernier, who examined it in Florence around 1657 and recorded its weight as approximately 139.5 carats — a figure close enough to the later 137.27-carat measurement to suggest the same stone, with minor discrepancy attributable to differences in carat standards between eras. Tavernier's account in his Les Six Voyages (1676) remains one of the most important primary sources for the stone's early appearance and cut.

The Medici connection gave the diamond its most enduring name. Florence was the seat of Medici power, and the stone was displayed as a centrepiece of Tuscan grand-ducal magnificence. When the Medici line became extinct in the male line with the death of Gian Gastone de' Medici in 1737, the grand duchy of Tuscany passed to Francis Stephen of Lorraine, husband of the Habsburg empress Maria Theresa. The Florentine Diamond passed with it, entering the Habsburg-Lorraine treasury and thenceforth the Austrian imperial regalia.

In the Habsburg Imperial Treasury

Under Habsburg ownership the Florentine was housed in Vienna, where it was incorporated into various state jewels and displayed as part of the imperial treasury (Schatzkammer). It was mounted at different periods in hat ornaments, brooches, and ceremonial orders, though it was also frequently exhibited unmounted as a loose stone of singular historical importance. Contemporary accounts from the eighteenth and nineteenth centuries confirm its presence in Vienna and describe its unusual cut and pale yellow colour with consistent detail, providing a reliable chain of custody through the imperial period.

The diamond was considered one of the great treasures of the Habsburg crown, ranked alongside the Orlov in the Russian imperial collection or the Regent in the French treasury as a stone whose value was as much historical and dynastic as purely monetary. It was insured and inventoried with the other Habsburg crown jewels and was not, so far as the historical record shows, pledged or sold during the financial pressures of the nineteenth century.

Disappearance After 1918

The collapse of the Austro-Hungarian Empire at the end of the First World War precipitated a crisis for the Habsburg crown jewels. Emperor Karl I abdicated in November 1918, and the new Austrian republic claimed the imperial treasures as state property. The Florentine Diamond was recorded in the Habsburg treasury at the time of the abdication, but it subsequently vanished from the documented record.

The most widely accepted account of its disappearance holds that members of the Habsburg family, or agents acting on their behalf, removed the stone — along with other portable valuables — when the imperial family went into exile. Karl I and his family left Austria in 1919, eventually settling in Madeira, where the emperor died in 1922. The diamonds and jewels taken into exile were reportedly entrusted to various intermediaries for safekeeping or liquidation. One account, which has circulated among jewellery historians though it has not been definitively confirmed, suggests the Florentine was taken to South America — possibly Argentina — in the early 1920s and there recut to disguise its identity before being sold. If this account is accurate, the stone no longer exists in its historic 137.27-carat, 126-facet form, and any fragments would be effectively unidentifiable without the original crystal to compare them against.

The Austrian government pursued claims against the Habsburg family for the return of crown jewels for decades after 1918, and some items were eventually repatriated. The Florentine Diamond was not among them, and no government, institution, or private collector has come forward with a credible claim to possess it. The stone is listed among the great lost diamonds of history alongside such vanished treasures as the Beau Sancy (which was in fact later rediscovered) and the various stones dispersed from the French crown jewels at auction in 1887.

Gemmological Significance

Beyond its historical drama, the Florentine is gemmologically significant for several reasons. Its double rose cut with nonagonal symmetry is, so far as the record shows, unique among diamonds of its size. Rose cuts of various forms were the dominant fashioning style for large diamonds from roughly the fifteenth through the seventeenth centuries, before the development of the brilliant cut displaced them; but the nine-sided outline and the 126-facet arrangement of the Florentine represent an extreme elaboration of the form that has no close parallel in surviving stones. The cut speaks to a lapidary tradition — almost certainly Indian or early Dutch — in which the natural octahedral crystal form of the diamond was exploited and extended rather than radically remodelled.

The stone's colour, a pale greenish yellow, is consistent with diamonds of Type Ia character, in which nitrogen aggregates in pairs (IaA centres) and clusters (IaB centres) produce yellow absorption. The greenish modifier in such stones is sometimes attributed to natural irradiation during geological residence, a phenomenon well documented in yellow and green diamonds from Indian and Brazilian deposits. Without spectroscopic analysis, however, any assignment of colour origin or nitrogen configuration to the Florentine must remain speculative.

The recorded weight of 137.27 carats places the stone in a rarefied category. Fewer than a handful of faceted yellow diamonds of comparable size are known to exist, and most of those — the Tiffany Yellow at 128.54 carats, for instance — are products of the modern brilliant-cutting era and bear no resemblance in form to the Florentine's archaic rose structure.

The Question of Recutting

The hypothesis that the Florentine was recut after its disappearance is both plausible and deeply troubling to gemmological history. A stone of 137.27 carats in a double rose cut would, if converted to a modern round brilliant or cushion brilliant, yield a finished stone in the range of perhaps 80 to 100 carats depending on the proportions chosen — still a stone of extraordinary size and value, but one that would bear no obvious physical connection to its predecessor. The nine-sided outline and the 126 facets of the original would be entirely destroyed in such a recutting, and the resulting stone would present to a modern laboratory as simply a large fancy yellow diamond of uncertain provenance.

This possibility has led some historians to speculate about large yellow diamonds that appeared on the market in the 1920s and 1930s without clear provenance. None of these speculations has been confirmed, and the identification of any existing stone as a recut Florentine would require extraordinary evidence — ideally, inclusions or growth features that could be matched to historical descriptions or to other diamonds known to have originated from the same rough crystal, a comparison that is not currently possible.

Legacy and Cultural Resonance

The Florentine Diamond occupies a particular place in the imagination of gem historians and collectors because its loss is so recent and so well documented. Unlike the diamonds of antiquity whose trails go cold in medieval obscurity, the Florentine was a fully inventoried, multiply described, photographed (in at least some period illustrations) treasure that disappeared within living memory of the present era. The political circumstances of its disappearance — the fall of a centuries-old empire, the chaos of post-war exile, the liquidation of dynastic assets by a family stripped of its throne — give its story a historical weight that transcends mere gem lore.

It is also a reminder that the permanence of diamonds, so often invoked in commercial contexts, applies to the mineral itself and not to the human structures — dynasties, empires, collections — that give individual stones their meaning and their names. The Florentine endures, in all probability, as a physical object somewhere in the world. Whether it endures as the Florentine — as the nine-sided, 126-faceted, 137.27-carat pale yellow rose that Tavernier admired in the Medici treasury in 1657 — is a question that may never be answered.

Further Reading

• GIA Gems & Gemology — research on historic diamonds
• GIA: Famous Diamonds overview