The Kohinoor or Koh-I-Noor diamond is a famous diamond currently in the hands of the British Crown. Like many famous named diamonds, the Kohinoor is accompanied by numerous legends, including stories that suggest it is cursed with violence. The history of the diamond has certainly been accompanied with violent struggle, but this may have less to do with a curse than it does with the value of the diamond; the Kohinoor diamond was once one of the largest diamonds in the world, and large diamonds fetch high prices.

The origins of this diamond are a bit mysterious. The Kohinoor diamond appears to have been mined in Kollur Mines of the Andhra Pradesh region of India, with the first firm recorded story about the diamond dating to the early 16th century. Indian legends, however, state that the Kohinoor diamond is actually thousands of years old, with some stories saying that it was created by the gods while others say that it was found in the Godavari River.

Whatever the origins of the diamond, the 186 Kohinoor was one among many fabulous items owned by the Mughal Emperors of India. It passed among a number of owners, sometimes in rather suspicious ways, before being seized by the British East India Company and presented to Queen Victoria. The Kohinoor diamond was one of the most notable items looted from India by the British, and it continues to be brought up in diplomatic negotiations, with several attempts to negotiate the return of the diamond to its homeland.

Historically, Indian diamond cutters focused on preserving the size of a diamond, not on cutting for brilliance. As a result, the Kohinoor diamond failed to astound the public or the Crown when it was brought to England. Prince Albert ordered the diamond recut, transforming the diamond into a 105 carat brilliant. The loss of around 40% of the diamond's size was viewed as an acceptable trade for a stone of much higher quality.

It has been said that whoever owns the Kohinoor diamond will control the world. The British Empire certainly did control large chunks of the world at some point, although its influence has dwindled considerably since the years of the Anglo-Sikh War when the Kohinoor was taken from India. Today, the diamond can be seen on display at the Tower of London along with other objects in the Crown Jewels, and it is brought out for ceremonial occasions.