The phrase 'Lahore Diamond' is not a stable name in the historic-gemstone literature. It is used in older popular accounts, and occasionally in nineteenth-century English sources, to refer to one of several Indian diamonds in the treasury at Lahore at the time of the British annexation of the Punjab in 1849. The most consequential of these was the Koh-i-Noor itself, which was surrendered to the East India Company under the Treaty of Lahore and is sometimes, in casual usage, called 'the Lahore diamond' as a result. Other large diamonds were also in the Sikh treasury at Lahore, and the term has been applied at various times to several distinct stones, with the result that the name carries no single unambiguous referent in the modern scholarly record.

The Sikh treasury at Lahore

The Toshakhana, the treasury of the Sikh Empire established by Maharaja Ranjit Singh, was maintained at Lahore (in present-day Pakistan) and contained, at the time of Ranjit Singh's death in 1839, a collection of jewels assembled over the course of his reign and inherited from his predecessors. The most famous component of the treasury was the Koh-i-Noor, acquired by Ranjit Singh in 1813 from Shah Shujah of Afghanistan. Other significant stones included the Timur Ruby (in fact a balas spinel), the Daria-i-Noor (variously identified) and a quantity of large pearls. The Sikh wars and the British annexation in 1849 led to the formal surrender of the Toshakhana under the Treaty of Lahore, with the Koh-i-Noor passing to Queen Victoria and other items being sold or distributed within the East India Company's establishment.

The 'Lahore Diamond' usage

The term 'Lahore Diamond' appears in some nineteenth-century Anglophone sources as a generic descriptor for the Koh-i-Noor in its character as the principal stone of the Lahore treasury. It also appears in older, less reliable popular accounts as a name for separate large stones supposedly in the Lahore treasury, but none of these alternative attributions has survived modern critical scrutiny in published scholarly works. The Dalrymple-Anand 2017 monograph on the Koh-i-Noor, the standard modern reference, treats the Koh-i-Noor as the only 'Lahore Diamond' for which there is reliable historical documentation. Other diamonds said in nineteenth-century sources to have been in the Lahore treasury, including unnamed large stones, are insufficiently documented to support distinct identifications.

Confusion with other names

The 'Lahore Diamond' confusion is part of a wider pattern of unstable nomenclature in the Indian diamond record. Several large historic Indian diamonds have circulated under multiple names at different periods, including the Daria-i-Noor (the 'Sea of Light', applied to at least two different stones, one in Iran and one in Bangladesh), the Akbar Shah Diamond, the Shah Diamond and the Great Mogul Diamond. Cross-identifications among these stones have been attempted by various scholars, with mixed results. The 'Lahore Diamond' designation, where it appears, should therefore be read carefully against the source's context: a casual usage of the period for the Koh-i-Noor, an older popular attribution to an unidentified stone, or a separate name applied to a documented stone elsewhere catalogued.

Practical guidance

For the modern jewellery historian or trade research, the term 'Lahore Diamond' should be treated as an unstable historical designation rather than as identifying a specific stone. References to it in nineteenth-century English sources should be checked against the Koh-i-Noor literature, the Royal Collection Trust documentation, and the broader Indian diamond historiography. In modern auction or trade contexts the term is essentially never used as a primary descriptor, and a stone offered as 'the Lahore Diamond' would merit considerable due-diligence scrutiny of its provenance documentation.

The treaty context

The 1849 Treaty of Lahore, which formally transferred the Koh-i-Noor from Maharaja Duleep Singh (then a child) to Queen Victoria, is the legal-historical anchor for any stone designated by reference to Lahore in the British-Indian context. The treaty's Article 3, which specifically named the Koh-i-Noor, is the document by which the diamond passed from the Sikh Empire to the British Crown, and the Royal Collection Trust holds the diamond on the constitutional basis that flows from that treaty. Repatriation claims advanced since Indian independence, by India, Pakistan, Afghanistan and Iran, contest aspects of the treaty's circumstances but do not, on the present legal status, displace the British title.