The Great Mogul is among the most celebrated and most tantalising vanished gemstones in recorded history: a diamond of extraordinary size reportedly discovered in the Golconda region of India during the mid-seventeenth century, presented to the Mughal emperor Shah Jahan, and subsequently lost to the historical record following the catastrophic sack of Delhi in 1739. Known principally through the account of the French jeweller and traveller Jean-Baptiste Tavernier, who examined it in 1665, the Great Mogul occupied a singular position in the imagination of European gem traders and courts for generations. Its ultimate fate — whether it was destroyed, secreted away, or recut beyond recognition — remains one of gemmology's most enduring unsolved questions.

Discovery and Provenance

The stone is believed to have been found in the Kollur mine on the Krishna River in the Golconda region of the Deccan plateau, the same alluvial and volcanic pipe system that yielded the Koh-i-Noor, the Hope Diamond, and the Nassak Diamond. Golconda was not a single mine but a trading centre and sultanate whose name became synonymous with Indian diamonds of the finest quality — stones characterised by their exceptional clarity, their faint bluish or steely fluorescence, and the absence of nitrogen-related colour that renders so many Indian diamonds of this era a pure, water-white transparency.

The precise date of discovery is unrecorded, but circumstantial evidence places it in the 1640s or early 1650s. According to Tavernier's account, the stone was found during the reign of Shah Jahan (r. 1628–1658), the fifth Mughal emperor and builder of the Taj Mahal, and was presented to him as a tribute — a gesture consistent with the Mughal practice of requiring that exceptional gemstones of a certain size be offered to the emperor before entering private trade. The rough weight, as reported by Tavernier, was 900 ratis, a traditional Indian unit of measurement. Tavernier converted this to 280 carats using the equivalence he applied throughout his Les Six Voyages, though scholars have noted that the precise conversion factor he employed was not always consistent, introducing some uncertainty into the figure.

Tavernier's Account

Jean-Baptiste Tavernier made six voyages to Persia and India between 1631 and 1668, trading in gems and acting as an informal commercial diplomat between Eastern courts and European buyers. His Les Six Voyages de Jean-Baptiste Tavernier, first published in Paris in 1676, remains the primary documentary source for several of the great Indian diamonds. When Tavernier was received at the Mughal court in 1665 — by then under the emperor Aurangzeb, who had deposed his father Shah Jahan — he was shown the imperial treasury and permitted to examine and weigh numerous stones.

Tavernier described the Great Mogul as a round, rose-cut stone of exceptional size, resembling in form half of an egg. He recorded its weight at the time of his examination as approximately 280 carats — the rough having already been cut by this point. He further noted that the cutting had been entrusted to a Venetian lapidary named Hortensio Borgio, and that the result was considered deeply unsatisfactory. Aurangzeb, according to Tavernier, was so displeased with Borgio's workmanship that he fined the lapidary ten thousand rupees rather than paying him for his labour — a punishment that underscores both the stone's immense value and the perceived incompetence of its fashioning. Tavernier's own assessment was that the cut was poorly proportioned, wasting significant weight and failing to maximise the stone's brilliance.

The description — a large, high-domed rose cut, round in plan, water-white or very faintly tinted — is consistent with Indian cutting practice of the period, which favoured preserving weight over optimising light return. Rose cuts of this era were ground rather than faceted in the modern sense, and a stone of 280 carats in this form would have been a remarkable, if somewhat inert, object: more a symbol of sovereign power than a vehicle for optical display.

The Cut and Its Criticism

Hortensio Borgio's reputation in the historical record rests almost entirely on this single, disastrous commission. European lapidaries working in India during the seventeenth century occupied an ambiguous position: they brought technical knowledge of faceting styles unknown to Indian craftsmen, but they also worked under enormous pressure, on stones of incalculable value, with tools and abrasives that were often improvised. The penalty Borgio suffered — financial ruin at the hands of Aurangzeb — was not unusual in a court where the emperor's displeasure could take far more severe forms.

The criticism of the cut raises an important gemmological question: what exactly was wrong with it? Tavernier does not specify whether the fault lay in the proportions, the symmetry, the finish of the facets, or the overall yield from the rough. Given that the stone reportedly weighed 900 ratis in the rough and approximately 280 carats after cutting, the yield was roughly 56 per cent by weight — not dramatically low for a rose cut of this period, which suggests the criticism may have centred on the optical performance or the shape rather than on excessive weight loss. Some later commentators have speculated that the stone had a significant natural flaw that Borgio was unable to avoid, and that the emperor's anger was partly displaced frustration at the rough's own limitations.

Disappearance: The Sack of Delhi, 1739

The Great Mogul remained in the Mughal imperial treasury through the reigns of Aurangzeb (d. 1707) and his successors. The treasury was kept at the Red Fort in Delhi, and its contents — accumulated over more than a century of Mughal conquest and tribute — represented one of the greatest concentrations of gemstones and worked jewellery in the world. This concentration made it an irresistible target.

In February 1739, the Persian emperor Nādir Shah crossed the Indus with an army that had already dismantled the Safavid empire and reorganised Persia under his own rule. He defeated the Mughal forces at the Battle of Karnal and entered Delhi in March. What followed was one of the most devastating episodes of looting in South Asian history. Nādir Shah seized the Peacock Throne — the jewel-encrusted ceremonial seat commissioned by Shah Jahan, which incorporated hundreds of rubies, emeralds, and diamonds — along with the Koh-i-Noor, the Taj-e-Mah, and an estimated 700 million rupees' worth of treasure. He departed Delhi in May 1739, taking the Mughal treasury with him to Persia.

It is at this point that the Great Mogul vanishes from the documentary record. No Persian inventory from Nādir Shah's treasury, no subsequent European traveller's account, and no court chronicle from Isfahan or Mashhad makes unambiguous reference to a stone matching Tavernier's description. Whether the Great Mogul was among the stones carried to Persia, whether it was broken up or recut during or after the sack, or whether it had already left the treasury by some other route before 1739, cannot be determined from surviving sources.

Theories of Identification

The disappearance of a 280-carat diamond does not go unnoticed, and gemmologists and historians have proposed several candidates for the stone's later identity. None has achieved scholarly consensus.

The Orlov Diamond

The most frequently cited candidate is the Orlov, now set in the Imperial Sceptre of Russia and held in the Kremlin Armoury. The Orlov is a large, high-domed rose cut of Indian origin, weighing 189.62 carats, with a faint bluish-green tint and exceptional clarity. Its shape — described as resembling half of a pigeon's egg — corresponds closely to Tavernier's description of the Great Mogul. The Orlov's provenance before the eighteenth century is obscure: it appears in the historical record in Amsterdam in 1775, when it was purchased by Count Grigory Orlov and presented to Catherine the Great. The gap between 1739 and 1775 is not implausibly long for a stone that had been looted, transported to Persia, and then found its way into European trade.

The principal argument against the identification is weight: 189.62 carats is significantly less than 280 carats, and even allowing for repolishing or minor recutting, the discrepancy is substantial. Proponents of the identification argue that Tavernier's weight conversion was imprecise, or that the stone was recut after leaving the Mughal treasury. Opponents note that a reduction of nearly 90 carats would represent a dramatic recutting, not a minor repolishing, and would almost certainly have been noted somewhere in the documentary record.

The Koh-i-Noor

A second theory proposes that the Great Mogul and the Koh-i-Noor are the same stone. The Koh-i-Noor — now 105.6 carats in its current brilliant cut, set in the Crown of Queen Elizabeth The Queen Mother — was certainly among the stones taken by Nādir Shah in 1739, and its Indian origin and Golconda provenance are well established. However, the Koh-i-Noor's weight before its recutting by the Duke of Wellington's lapidary in 1852 was recorded at approximately 186 carats, and earlier descriptions suggest it was always a relatively flat, irregular stone rather than the high-domed form Tavernier described. The physical descriptions are sufficiently different that most gemmologists treat the Koh-i-Noor identification as unlikely.

Other Candidates

Smaller-scale proposals have linked the Great Mogul to the Darya-ye-Noor (now in the Iranian Crown Jewels collection), a pale pink diamond of approximately 182 carats, and to various unidentified stones in the former Persian treasury. The Darya-ye-Noor's pink colour, however, is inconsistent with Tavernier's description of a colourless or near-colourless stone, making this identification difficult to sustain.

A more cautious position, adopted by several modern gemmological authorities, is that the Great Mogul may simply have been broken into multiple pieces — either during the chaos of the 1739 sack or subsequently — and that its component parts are now unidentifiable. Diamond cleaving and bruting were practised in India long before European contact, and a large, imperfect stone might have been deliberately divided to remove inclusions or to produce more commercially tractable pieces.

Gemmological Significance

The Great Mogul occupies a specific and important place in the history of gemmology for reasons beyond its romantic disappearance. Tavernier's account of it — and of the other stones he examined in the Mughal treasury — constitutes one of the earliest systematic attempts by a European to record the weights, colours, and forms of large gemstones in a non-European context. His use of the rati and his conversion to carats, however imprecise, established a methodology that later travellers and gem traders would refine.

The stone also illustrates the tension between Indian and European cutting traditions that characterised the seventeenth and eighteenth centuries. Indian lapidaries prioritised weight retention and the preservation of the rough's natural form; European craftsmen, increasingly influenced by the development of the brilliant cut (attributed to Vincent Peruzzi in the late seventeenth century), prioritised optical performance. The Great Mogul — cut in a transitional style by a European working under Indian court conditions — embodied this tension literally in its facets.

Finally, the Great Mogul serves as a reminder that the historical record of famous gemstones is far less complete than popular accounts suggest. The stones that can be traced continuously from mine to modern owner are the exception; the Great Mogul, like the Florentine Diamond and several other celebrated historical stones, belongs to the larger category of gems whose histories are reconstructed from fragments, whose identities are disputed, and whose physical reality may be irrecoverably dissolved into later, unrecognisable forms.

In the Trade and Popular Culture

The Great Mogul has never been offered at auction in any identified form, and no major gemmological laboratory has published a report linking a known stone definitively to it. It appears regularly in popular histories of famous diamonds and in museum catalogues discussing Mughal jewellery, typically as a cautionary example of the limits of historical gem documentation. The Kremlin Armoury's display of the Orlov notes the identification theory without endorsing it, a position that reflects the current scholarly consensus: intriguing, plausible in outline, unverifiable in detail.

For the working gemmologist or jewellery historian, the Great Mogul is most useful as a case study in source criticism. Tavernier's account is invaluable but not infallible; his weight conversions, his descriptions of colour, and his accounts of provenance must all be read with an awareness of his position as a commercial trader with interests in the stones he described. That said, his record of the Great Mogul is more detailed and more credible than many comparable accounts of the period, and the stone's existence as a distinct object in the mid-seventeenth century Mughal treasury is not seriously disputed by any authority.

Further Reading

• Gems & Gemology — articles on historical Indian diamonds (gia.edu)
• GIA Gem Encyclopedia — Diamond (gia.edu)