Legend has it that a French soldier tore it from the eye of an idol in a Hindu temple, and that later, it was given by Count Orloff to Empress Catherine the Great of Russia as a gift meant to regain her favour (it didn’t). These days, it can be admired at the Kremlin.
Here’s the actual legend in detail, from Famousdiamonds.tripod.com:
“A French soldier, who deserted and found employment in the neighborhood of Srirangem, learned that the temple contained the celebrated idol of a Hindu god, the eyes of which formed by two large diamonds of inestimable value. Thereupon he made a plan to seize the gems, a feat which necessitated years rather than months of planning, since no Christian was ever admitted beyond the fourth of the seven enclosures. So in order to effect his evil purpose, he embraced the Hindu faith and eventually obtained employment within the walls of the temple. By degrees he gained the confidence of the unsuspecting Brahmins and was allowed in as a frequent worshipper at the inner shrine, because of his apparent veneration for this particular divinity. Ultimately, he secured the appointment of guardian to the innermost shrine within which lay the object of his attention.
Then came the moment for which the Frenchman had waited so long, a stormy night that masked the idol in fitful shadows. He laid his sacrilegious hands upon the diety entrusted to his care and prized one of the diamond eyes out of its socket. Losing courage, he then fled the scene leaving the other diamond behind. He scaled the walls of the temple, swam the river and escaped into the surrounding jungle to the comparative safety of the English army encamped at Trichinopoly, and all the while the tempest raged. Finally, he made his way to Madras, where he sold the diamond for £2,000 to an English sea captain who brought it to London and sold it to a Jewish merchant for £12,000.”
Count Orloff went on to marry his cousin, and upon her death, he lost his mind and died shortly thereafter.
Admittedly, this is a gem with almost as much personality as the Hope Diamond – if less cursed. Discover a bit more about it here.