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The Sancy Diamond: one of the loveliest diamonds in the world

The rarity of certain precious stones and their heroic stories has resulted in some diamonds gaining a mythical status. One such stone is the Sancy Diamond, a diamond of no fewer than 55.23 carats and with a unique pale-yellow appearance. The diamond, which is one of the most beautiful diamonds in the world, has a turbulent history but it is now back in safe hands in France. What is the story behind the Sancy Diamond?

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What's the story behind the legendary Sancy Diamond?

The Sancy Diamond, a remarkable 55.23-carat pale yellow gem with a shield-shaped cut, has traveled through centuries of European history. First mentioned in 1477 after the Battle of Nancy, this precious stone journeyed from Portuguese possession to Nicolas de Harlay in 1570, who lent it to the French Court before selling it to England's James I (who gave it its name). The diamond later returned to France with exiled James II, who sold it to Louis XIV, only to be stolen during the French Revolution.

After resurfacing in 1828, the Sancy changed hands several times before finding its permanent home in the Louvre Museum in Paris. Although never officially valued, its worth is estimated at over six million euros, derived not only from its unique characteristics but also from its extraordinary historical significance that spans royal courts, revolutions, and aristocratic collections.

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The history of the Sancy Diamond

The Sancy Diamond was first mentioned in books in the year 1477. Charles the Bold lost the Battle of Nancy. He fled and was found dead two days later; he had fallen off his horse. He was succeeded by his daughter Mary of Burgundy (who was later at the cradle of the diamond engagement ring).  The diamond probably fell prey to the Portuguese during the battle, because the Sancy Diamond first appeared in Portugal.

Detailed ownership timeline and modern display

- circa 14th–15th century: Possible early origin narratives link the stone to medieval dowries such as the so-called Balle de Flandres; documentary certainty for this period is limited. Source: LangAntiques; Wikipedia.

- 1477: The diamond is first clearly attested in records after the Battle of Nancy and later appears in Portuguese possession. Source: Wikipedia.

- 1570: Nicolas Harlay de Sancy purchases the stone and lends it to the French court; it appears in inventories and is publicly worn during ceremonies. Source: Wikipedia; Ajediam.

- March 1605: Under financial pressure Harlay sells the diamond to King James I of England; the stone enters the English crown collection and is kept at the Tower of London for a time. Source: Wikipedia.-

- Mid-17th century (1657–1661): During the Stuart and continental upheavals the Sancy changes hands and becomes associated with Cardinal Mazarin’s collection and other collectors before reappearing in French royal circles. Source: Wikipedia; Ajediam.

- 1690: After James II’s defeat at the Battle of the Boyne the stone is sold to Louis XIV and returns to France, remaining part of royal regalia through the 18th century. Source: Wikipedia.

- 1792–1793: During the French Revolution several crown jewels, including the Sancy, are dispersed or stolen; the stone disappears from public inventories for decades. Source: Wikipedia; LangAntiques.

- 1828: The Sancy resurfaces and is recorded as acquired by Prince Anatole Demidov. Over the 19th century it passes between jewellers and private collectors. Source: Ajediam; NaturalDiamonds.

- 1906 and early 20th century: William Waldorf Astor purchases the Sancy and it remains within the Astor family for much of the 20th century. Source: Wikipedia; NaturalDiamonds.

- Late 20th century to present: Arrangements placed the Sancy on public display in France; today it is exhibited in the Louvre, notably within the Galerie d'Apollon, as part of the national collection. Museum catalogues and records provide accession and display context. Source: Wikipedia; NaturalDiamonds.

This timeline brings together documentary attestations and published provenance studies to clarify the stone’s complex chain of custody and its transitions between royal, private and museum contexts.
The stone stayed in Portuguese hands for almost a century before continuing its journey
Historic portrait of a nobleman wearing a gold chain and gemstone-studded ceremonial regalia - James I of England possessed the diamond for some time.
In 1570, the property owner of Sancy, Nicolas de Harlay, bought the precious stone to add to his collection of precious stones. De Harley clearly estimated its value because he decided not to sell the diamond. He lent the diamond to the French Court where pomp and circumstance were always in style. Until 1596, the Sancy was part of the French Court's jewellery collection, albeit as a borrowed object.

De Harley didn't want to sell the diamond, but he was forced to take measures in 1596 to save his financial situation. He decided to sell the diamond, but not to the French Court. James I of England made the winning bid and the diamond would then stay out of France for almost a century.

James II lost the Battle of the Boyne in 1690, fled to France and sold the diamond to Louis XIV, the Sun King. The Sancy remained at the French Court, but things went wrong during the riots of the French Revolution. Various rare diamonds were stolen, including the Sancy and The Blue Hope Diamond.
The precious stone reappeared in 1828 and the Russian Prince Anatoly Demidov bought the diamond. In 1865, the prince sold the Sancy to a French jeweller, after which William Waldorf Astor bought the stone in 1906 and gave it to his daughter-in-law as a wedding present.

Provenance: fact vs. fiction

Several origin stories circulate about the Sancy, and not all are equally documented. One recurring hypothesis links the diamond to medieval dowry inventories such as the so-called Balle de Flandres or to figures like Valentina Visconti, but primary records for the 14th–15th century remain incomplete, so these connections are plausible rather than proven. More concrete evidence begins in the late 15th century, when inventories and contemporary accounts place the stone in Portuguese and later French hands. Colourful anecdotes attached to the Sancy - dramatic pawn legends or curse tales - generally come from secondary storytelling and lack consistent archival support. Where modern scholars and museum catalogues verify transfers, those details form the reliable backbone of the diamond’s history; other accounts should be treated as legend unless corroborated by primary sources. Source: LangAntiques; Wikipedia.

How did the Sancy Diamond get its name?

James I of England gave the Sancy its name. He christened the diamond as the Sancy Diamond because he bought it from Nicolas de Harlay, property owner of Sancy. In the Tower of London, where it stayed for a while, the diamond had a plaque stating: 'bought of Sauncy'.

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The value of the Sancy Diamond

An etching of the Sancy diamond - An etching of the Sancy diamond
The Sancy is really unique, especially its colour. We can evaluate the French diamond on the basis of the 4 Cs:

  • Carat: 55.23
  • Colour: pale yellow
  • Cut: a symmetrical shield-shape with two identical surfaces
  • Clarity: unknown


The value of the diamond has never been calculated because its value is also in its amazing history. The diamond is currently estimated at just over six million euro. It is one of the most famous diamonds in the world.

Technical description and measurements

The Sancy is notable for both its size and its unconventional cut. Its recorded weight is 55.23 carats (11.046 grams) and catalogued dimensions are 25.7 mm × 20.06 mm × 14.3 mm. Rather than a standard brilliant, the stone presents as two crowns set back-to-back, sometimes called a double crown with no true pavilion. Each face shows a central pentagonal facet surrounded mainly by triangular facets. That double-crown geometry produces the shield-like outline and explains its relatively shallow profile for a stone of this carat weight.

Historical notes record surface wear consistent with centuries of handling: small scratches and abrasions that affect surface polish more than internal structure. Measured specific gravity values align with diamond (around 3.52), confirming identification despite the unusual cut. UV reactions have also been recorded: short-wave UV elicits a deeper yellow fluorescence, while long-wave UV can produce paler salmon-pink to faint greenish phosphorescence under certain conditions. Together, these dimensions, facet details and UV responses serve as objective identifiers for the Sancy. Measurements and observations follow published examinations by LangAntiques and Jobbins.

The Sancy diamond in modern times

Today, the Sancy Diamond is housed in the Louvre Museum in Paris, where it continues to attract visitors from around the world. Its enduring legacy as a symbol of luxury and craftsmanship makes it a source of inspiration for modern jewellery designers and collectors.

For jewellery enthusiasts and diamond collectors, the Sancy Diamond represents the epitome of timeless elegance and sophistication. Its storied past, unique characteristics, and symbolic meaning make it a gem that transcends generations, embodying the very essence of luxury and craftsmanship.

The French Crown Jewels

The Sancy Diamond holds a prominent place in the annals of French history. It was once a part of the French Crown Jewels, embellishing the regalia of monarchs. Its storied past includes stints in the hands of English kings, European aristocrats, and even thieves. Despite its tumultuous history, the Sancy has always found its way back to the limelight, a testament to its irresistible charm. Here’s a journey through time:

  • 16th Century: Acquired by Nicolas Harlay de Sancy, who lent the diamond to King Henry III of France.

  • 17th Century: Passed into the possession of the English crown under James I.

  • 19th Century: Incorporated into the French Crown Jewels, only to be stolen during the French Revolution.

  • Modern day: Now part of a private collection, the Sancy Diamond continues to captivate jewellery lovers worldwide.

Why buy diamonds from BAUNAT?

So, why buy diamond jewellery from BAUNAT? We also offer a customised service from a budget of €4,000. Working with our experts you can design diamond jewellery entirely how you want it. If you have any questions about our jewellery or about certain styles and trends, our experts are always on hand to provide advice.

The diamonds and other precious stones from BAUNAT are of course of the highest possible quality. BAUNAT buys its diamonds directly from the source, eliminating intermediaries and enabling us to offer jewellery online 30% to 50% cheaper. Moreover, we only work with high-quality materials. For the precious metals, this is 18 carat gold and 950 platinum.

Find out about the most famous diamonds in the world

With its rich history, the Sancy Diamond has become one of the most valuable diamonds in the world. Read more about other valuable diamonds.

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  • BAUNAT Antwerp

  • Fabienne, manager of the German market is able to guide every client with finding the right jewel. She takes care of most of the German orders, but also takes other task on her plate. Thanks to her six  years of experience at BAUNAT she acquainted well with the product and the marketing around it. Her degree in PR ensures that BAUNAT is well presented across all media channels. For anyone looking into a new investment opportunity, Fabienne is the perfect guide in this process. No question will be left unanswered, and she will help you every step of the way.

    Selected Bespoke Projects

    • Eternal Bloom bespoke engagement concept - Role: project lead for client briefing and prototype coordination. Fabienne translated personal design references into a 3D-printed prototype, supervised stone selection and ensured the finished piece matched the client’s vision and comfort preferences.

    • Personalized anniversary necklace - Role: design coordinator and quality overseer. She managed the custom design process from the initial sketch to final polishing, liaising between client and workshop to preserve proportions and finish.

    • Reimagined heirloom ring restoration and redesign - Role: client consultant and technical coordinator. Fabienne guided the client through options to modernize setting details while keeping sentimental elements, delivering a wearable result that respected the original piece.

    Her hands-on involvement in bespoke commissions ensures each custom order has a clear brief, careful prototype review and close follow-up with the workshop, so clients receive a tailored jewel that meets both aesthetic and practical expectations.

    Professional enquiries

    For speaking engagements, press requests or research collaborations, please send your message to BAUNAT’s communications team with the subject line: "Fabienne Rauw  -  Professional Enquiry." Include a brief description of the request and any relevant dates or documents. The communications team will route enquiries to Fabienne and provide guidance on next steps.

Fabienne, manager of the German market is able to guide every client with finding the right jewel. She takes care of most of the German orders, but also takes other task on her plate. Thanks to her six  years of experience at BAUNAT she acquainted well with the product and the marketing around it. Her degree in PR ensures that BAUNAT is well presented across all media channels. For anyone looking into a new investment opportunity, Fabienne is the perfect guide in this process. No question will be left unanswered, and she will help you every step of the way.

Selected Bespoke Projects

• Eternal Bloom bespoke engagement concept - Role: project lead for client briefing and prototype coordination. Fabienne translated personal design references into a 3D-printed prototype, supervised stone selection and ensured the finished piece matched the client’s vision and comfort preferences.

• Personalized anniversary necklace - Role: design coordinator and quality overseer. She managed the custom design process from the initial sketch to final polishing, liaising between client and workshop to preserve proportions and finish.

• Reimagined heirloom ring restoration and redesign - Role: client consultant and technical coordinator. Fabienne guided the client through options to modernize setting details while keeping sentimental elements, delivering a wearable result that respected the original piece.

Her hands-on involvement in bespoke commissions ensures each custom order has a clear brief, careful prototype review and close follow-up with the workshop, so clients receive a tailored jewel that meets both aesthetic and practical expectations.

Professional enquiries

For speaking engagements, press requests or research collaborations, please send your message to BAUNAT’s communications team with the subject line: "Fabienne Rauw  -  Professional Enquiry." Include a brief description of the request and any relevant dates or documents. The communications team will route enquiries to Fabienne and provide guidance on next steps.