The world's largest gemstone diamond is called "Cullinan", and its discovery is quite accidental. On January 25, 1905, the Premimir mine (also known as the Prime Minister's Mine) in South Africa (Azania) had a manager named Welsh who occasionally saw a gleaming thing on the ground of the mine. He with a knife to dig it up and saw that a huge gem diamond. Its weight is 30,247.75 carats using the old carat unit at the time (1 carat = 205 mg). Converted to the now common metric carat (1 carat = 200 mg) is 3106 carats, or 621.2 grams. The volume is about 5 × 6.5 × 10 cm, which is equivalent to the fist of an adult man. It is pure and transparent with a light blue hue and is the best grade of gem diamond. Until now, it is the largest gemstone diamond found in the world.
Cullinan is not a complete crystal, it is just a fragment of a large crystal. Cullinan was too big and no one could afford it at the time. Later, it was acquired by the local authorities of Transvaal in South Africa for £150,000. On December 9, 1907, it was presented to the British royal family for the birthday of King Edward III.
At the beginning of 1908, Cullinan was sent to Amsterdam, the most authoritative city in the Netherlands, and was handed over to Jos Azchar for processing. The processing fee was 80,000 pounds. Because the rough stone is too large, it needs to be broken into small pieces in advance according to plan. Breaking it up is an extremely difficult job, because if the research is not enough or the technology is not good, the huge gem will be broken into a pile of small pieces of little value.
The shredding work was carried out by the famous Dutch craftsman Jos Azchar. He spent several weeks studying Cullinan, built a glass model of its size and shape, and designed a set of tools. He first tested the glass model with these tools, and the results were opened as expected. After a few days of rest, on February 10, 1908, he and his assistant came to a special studio, clasped Cullinan in a large pliers, and placed a special steel wedge on it. Above the pre-milled groove. Jos Acharhall struck the steel wedge with a heavy stick, and with a bang, Cullinan did not move, but the steel wedge was broken. Aschard had a cold sweat on his face, and in the atmosphere that was as nervous as he was about to explode, he put a second steel wedge. Knocking hard again, this time, Curry was split into two halves exactly as scheduled, and Aschar was fainted on the floor.
After Cullinan was opened, three skilled craftsmen worked 14 hours a day and spent eight months. A total of 9 large diamonds and 96 small diamonds were ground. The total weight of the 105 diamonds is 1063.65 carats, which is 34.25% of the original weight of Cullinan. It can be seen that the weight loss of the diamond after processing into a diamond is large. The largest of the nine larger diamonds is called "African Star I", which is "Cullinan No. 1". It weighs 530.2 carats and is shaped like a teardrop. It has 74 faces. It is also the largest diamond in the world today, set on the king's scepter. The second largest is called "African Star II" and weighs 317.4 carats. It has a square appearance and has 64 faces. It is the second largest diamond in the world and is now set in the middle of the British Empire. The other 7 tablets weighed 94.4, 63.6, 18.8, 11.5, 8.8, 6.8 and 4.39 carats.
The nine large diamonds milled by Cullinan are all owned by the British royal family. Among them, "Cullinan I" and "Cullinan IV" were once set in the crown of Queen Mary made in 1911, and then removed from the collection of queens, and the crown was replaced by a replica of crystal . In 1919, another 1,500-carat gemstone diamond was found in the Premiere mine. The third in the world by weight. It is also a fragment of a large crystal and is similar in color to Cullinan. Therefore, some people think that it is the same large crystal fragment as Cullinan, so this diamond did not give it a special name.
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