gemology

What Is the Biggest Cut Diamond in the World: Verified Size, Origin, and History

The world’s largest cut diamond is the Golden Jubilee Diamond, a 545.67‑carat fancy brown diamond that was cut and polished in Thailand. Originally a 755.5‑carat rough sto...

Mara Ellison
What Is the Biggest Cut Diamond in the World: Verified Size, Origin, and History

What Is the Biggest Cut Diamond in the World

The world’s largest cut diamond is the Golden Jubilee Diamond, a 545.67‑carat fancy brown diamond that was cut and polished in Thailand. Originally a 755.5‑carat rough stone discovered in the Premier Mine of South Africa in 1985, it was fashioned by master cutters to maximize beauty and minimize visible inclusions. This verified, non‑heated fancy brown diamond has been mounted in a crown for display, distinguishing it in gem records and serving as a benchmark in discussions of size, value, and diamond classification.

The Golden Jubilee Diamond: Core Facts

As of the most recent authoritative gemological documentation, the Golden Jubilee Diamond holds the record for the largest faceted diamond in the world by cut weight. Its characteristics place it at the intersection of notable geology, careful craftsmanship, and public exhibition. The sections below detail its specifications, origin, and how it compares to other famous diamonds.

Key Specifications

AttributeVerified DetailSource Type
NameGolden Jubilee DiamondGemological Institute
Carat Weight (Cut)545.67 caratsLaboratory Report
Rough Weight755.5 caratsMining Record
Color GradeFancy BrownLaboratory Grading
TreatmentNon‑heatedLaboratory Disclosure
ShapeShield (Trillion) cut with 74 facetsCutting Record
Cutting LocationThailand (Kompong Speu)Trade Publication
Year of Discovery1985Mining Report
Year of Cutting Completed1989Trade Publication

Origin: From South Africa to Thailand

The rough diamond was found in 1985 at the Premier Mine in Cullinan, South Africa, the same mine that produced the Cullinan I and Cullinan II diamonds set in the British Crown Jewels. After acquisition and evaluation, the stone was purchased by a group of Thai jewelers led by Henry Ho, who coordinated the cutting plan. The complex cutting process, which lasted about four years, was intended to preserve as much weight as possible while improving clarity and color appearance, resulting in the large, cushion‑like shield shape known today.

Classification and Identification Details

Diamond classification combines measurements with optical and physical properties. The Golden Jubilee is classified as a Type IIa diamond, meaning it has minimal nitrogen impurities and tends to be more chemically pure. Its brown color is attributed to plastic deformation (graining) during its formation deep in the Earth and subsequent cutting. Laboratories note it as non‑heated, indicating no high‑temperature treatment was used to alter color or clarity—a factor that affects both classification and value.

Notable Comparisons

While the Golden Jubilee holds the record for cut weight, other diamonds are notable depending on context. The Cullinan I (Great Star of Africa) at 530.2 carats is the largest clear cut diamond by colorlessness, set in the Sovereign’s Scepter. The Golden Jubilee is larger in carat weight but is classified as fancy brown, which places it in a different aesthetic and market category than colorless benchmark stones. Understanding these distinctions clarifies why multiple stones can each claim ‘largest’ in different respects.

Comparison DiamondCarat Weight (Cut)ColorRecord Context
Golden Jubilee545.67Fancy BrownLargest cut diamond by weight
Cullinan I530.2ColorlessLargest colorless cut diamond; in Crown Jewels
Excelsior Diamond (rough)995Colorless (rough)Largest rough diamond from South Africa (not cut)
Cullinan II317.4ColorlessPart of the Crown Jewels

Market Context and Valuation Considerations

Because the Golden Jubilee is a non‑heated fancy brown diamond of exceptional size, its valuation reflects both rarity of size and market appetite for treated versus untreated color. Large fancy brown diamonds are generally less expensive per carat than comparable colorless stones, but premiums exist for vivid intensities and history. Insured value estimates for the Golden Jubilee commonly appear in the range of tens of millions of U.S. dollars, though exact figures are not publicly disclosed and can vary with market conditions, buyer interest, and exhibition context.

Preservation and Public Display

The diamond has been publicly exhibited and is recognized in gemological and trade literature as a benchmark for large‑stone craftsmanship. It is typically mounted in a ceremonial crown or display setting for exhibitions, underscoring its role as a cultural as well as commercial asset. Its long‑term preservation reflects standard best practices for major colored diamonds: controlled lighting, humidity management, and secure storage when not on view.

Frequently Asked Questions

  • Is the Golden Jubilee Diamond the largest diamond ever found? It is the largest cut and polished diamond by carat weight. The largest diamond rough ever found is the Cullinan Rough (over 3,000 carats), but that was not faceted.
  • Does its brown color affect its value compared to colorless diamonds? Generally, highly saturated fancy colors command per‑carat premiums, but large fancy browns are typically valued below comparable colorless stones; the Golden Jubilee’s value is primarily tied to its size and history.
  • Has the diamond ever been re‑cut? No; it has remained in its original shield shape since 1989 to preserve its recorded weight and identity.
  • Can I see the Golden Jubilee Diamond in person? It is occasionally exhibited at gem and jewelry shows and by arrangement with its owners; it is not part of a permanent public museum collection.

Summary

The Golden Jubilee Diamond is the largest cut diamond in the world by carat weight, weighing 545.67 carats after its 1985 discovery in South Africa and careful cutting in Thailand completed in 1989. As a non‑heated fancy brown diamond of Type IIa composition, its value, classification, and conservation are well documented by gemological authorities. Understanding its distinctions from colorless benchmarks clarifies its place in gemstone records and the broader market for rare large diamonds.

tags: diamond, gemology, largest cut diamond, Golden Jubilee, fancy brown diamond

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