The Koh-i-noor is most likely the simplest known of all diamond gems. There's a practice that it absolutely was taken in 1304 from a rajah at Malwa, whose family had held it for centuries. It is believed to possess been guarded with alternative treasures at Delhi until 1739, when it had been carried off by Nadir Shah of Persia. Once further adventures the diamond was surrendered to the East India Company, whose directors presented it to Queen Victoria of England. It had been a badly cut diamond that lacked brilliance, but it weighed 191 carats. Queen Victoria had it recut by Garrards of London in 1852, and therefore the gem currently weighs 109 carats. It's among the English crown jewels.

The Great Mogul was the largest Indian diamond known. The rough stone weighed 817 carats, but inexpert cutting later reduced it to 287.five carats. The domed, rose-cut Orlov was one of the Russian crown jewels. Legend says that it was one of the eyes of an idol in a Brahman temple. It absolutely was eventually sold to Count Orlov, once a favorite of Catherine the Great. He gave the gem to Catherine, hoping the gift would restore him to favor, however it did not. As cut, the stone weighs 199.six carats.

The Blue Tavernier, a 112.5 carat Indian diamond, was taken to France within the 17th century. King Louis XIV bought it and had it recut to regarding sixty eight carats. In 1792 it was stolen, along with the Regent and therefore the Sancy. The Regent was recovered quickly, and therefore the Sancy in regarding 1828, but the Blue Tavernier was never found. In 1830, however, the 45.5-carat blue diamond currently called the Hope appeared on the market. Some gem experts believe that the Hope diamond could be a recut version of the lost Blue Tavernier.

The Regent, or Pitt, diamond, that weighed 410 carats within the rough, was found in India in 1701. Sir Thomas Pitt, governor of Madras, India, bought it and had it cut right down to 140.5 carats. In 1717 Pitt sold it to the regent of France. Later Napoleon had it set in the hilt of his sword. Once his fall it was placed within the Louvre. The Excelsior, discovered in South Africa in 1893, weighed concerning 995 carats. From this stone were cut twenty one fine stones, ranging in weight from less than one to more than 70 carats.

The biggest diamond ever found was the Cullinan. It was taken in 1905 from the Premier mine in Transvaal, South Africa. It weighed 3,106 carats (1.3 pounds; or 0.half-dozen kilogram). In 1907 the Transvaal government presented it to King Edward VII. The following year it had been cut into nine large and regarding one hundred small stones. The larger stones are called Stars of Africa, however they're additionally known as Cullinan I, II, III, and so on. Cullinan I (530.2 carats) is ready within the British Royal Scepter; Cullinan II (317 carats) is in the British State Crown.

The Jacobus Jonker (726 carats) was named for the prospector who found it in Transvaal in 1934. It had been the primary giant diamond cut in the United States, where 12 gems were cut from it. The Vargas diamond (726.6 carats), discovered in 1938 in Brazil, was cut into twenty nine gems. In 1945 a 770-carat diamond, the biggest ever taken from alluvial deposits, was dug up alongside the Woyie River in Sierra Leone.

Synthetic diamonds resemble natural diamonds in most elementary properties but could differ from them in size, shape, and impurities. They are used chiefly for industrial purposes, like in making grinding wheels for shaping and sharpening tungsten carbide tools. Since 1960 these have been made on a commercial scale. Within the late twentieth century new artificial processes created diamonds even higher suited for industrial use than natural diamonds.