The Cullinan Diamond is the largest diamond ever discovered. Unearthed in 1905 at the Premier No. 2 mine near Cullinan, South Africa, it weighed 3,106 carats in the rough. Its exceptional clarity and color led to faceting into multiple polished stones, including the Great Star of Africa and the Second Star of Africa set in the British Crown Jewels. This verified profile explains the discovery, recovery, and key attributes of the Cullinan while distinguishing it from other large diamonds and clarifying how its size is measured and recorded.
Discovery and Recovery
On 26 January 1905, surface manager Frederick Wells found a 3,106-carat diamond embedded in the wall of the Premier Mine. At the time, the Premier Mine (later renamed Cullinan Mine) was operated by the Premier Diamond Mining Company. The stone was too large to be used in standard diamond tools, so it was transported to London for assessment under tight security. Subsequent analysis confirmed it was a single, high-quality crystal of geminaI origin, setting the stage for its careful division and polishing.
Transport and Cutting
To prevent theft, the rough diamond was sent via registered parcel to London, disguised as an ordinary package. In London, it was presented to King Edward VII, who commissioned I. J. Asscher & Co. in Amsterdam to cut the stone. Joseph Asscher studied the crystal for weeks before splitting it into two major pieces in 1908. The resulting polished stones included the 530-carat Cullinan I (Great Star of Africa) and the 317-carat Cullinan II (Second Star of Africa), both set in the Imperial State Crown and the Sovereign’s Scepter, respectively.
Measured Size and Notable Attributes
Size for gem-quality rough and polished diamonds is recorded in carats, with one carat equaling 200 milligrams. The Cullinan Diamond’s original rough mass of 3,106 carats is a verified physical measurement, not an estimate. Its clarity is classified as Type IIa, meaning it contains few to no nitrogen impurities, and it exhibits a color grade described as colorless with a very slight blue nuance. These attributes contribute to its recognition as the world’s largest gem-quality diamond ever recovered.
| Attribute | Verified Detail | Source Type |
|---|---|---|
| Name | Cullinan Diamond | Historical mining records |
| Rough Weight | 3,106 carats | Mine production log |
| Polished Stones | Cullinan I (530 ct), Cullinan II (317 ct) | Asscher cutting reports |
| Location | Cullinan, South Africa (Premier No. 2 mine) | Geological survey |
| Year of Discovery | 1905 | Mining company archives |
| Current Setting | Part of the British Crown Jewels | Crown Jewels inventory |
Size Context and Comparisons
To contextualize the Cullinan’s scale, one carat equals 0.2 grams; therefore, the rough crystal had a mass of about 621 grams. For reference, most fine gem diamonds are under 10 carats, and even large faceted diamonds in museum collections typically weigh under 500 carats. The Cullinan remains unique in exceeding 3,000 carats, a benchmark not approached by any rough diamond discovered since. The next largest recorded gem diamond, the Excelsior, weighed 995 carats, less than one-third of the Cullinan’s mass.
Significance in Jewelry and Heritage
The cut Cullinan stones are integral components of British Crown Jewels. Cullinan I is set in the Imperial State Crown, worn annually at the State Opening of Parliament, while Cullinan II is set in the Sovereign’s Scepter. Their visibility in ceremonial regalia underscores the diamond’s cultural importance beyond mere size. As a result, the Cullinan functions simultaneously as a geological specimen, a historical artifact, and a symbol of sovereign regalia.
Common Misconceptions and Clarifications
A frequent misconception is that the Cullinan was the largest crystal of any mineral; in reality, other minerals such as boron nitride (e.g., from the Popigai impact structure) exist in larger crystalline forms, but they are not diamond. Another confusion arises from uncut stones marketed as ‘largest diamond’ that are often non-gem material or synthetic. The Cullinan is a natural, gem-quality diamond crystal that was definitively identified, weighed, and documented. Its verified status is supported by mining company records and subsequent gemological analysis.
Preservation and Public Access
Today, the cut and polished Cullinan diamonds remain in the Crown Jewels, which are held in the Tower of London when not in use. Public display is occasional and regulated, aligning with conservation protocols for historic regalia. The continued protection of these stones reflects their ongoing value as both cultural heritage and objects of scientific interest. Advances in imaging and measurement techniques ensure that their attributes remain documented for future research.
Conclusion
The Cullinan Diamond holds the verified record as the largest gem-quality diamond ever found. Its discovery in 1905, careful recovery, and expert cutting produced stones of historic significance that are now central to the British Crown Jewels. By distinguishing confirmed measurements from estimates and clarifying context around size, quality, and preservation, this profile provides a reliable reference for understanding what makes the Cullinan the largest diamond in the world.