PARIS, Sept 20 (Reuters) - In a bid to drum up investor appetite for rough, natural diamonds, mining company Lucara Diamond Corp (LUC.TO) and manufacturer HB Antwerp on Monday unveiled a 1,175-carat diamond in New York City. The companies are billing the stone as the largest rough diamond to be shown in the United States, and the third-largest to be discovered. Reuters could not independently verify these claims. HB Antwerp told Reuters it has yet to decide whether the uncut diamond will be cut into polished stones. The massive diamond was unveiled at the Whitby Hotel in upper midtown Manhattan, kicking off a week of viewings. The uncut stone was one of three diamonds of over a thousand carats extracted from the Karowe Mine in Botswana in recent years. In 2020, the two companies teamed up with Louis Vuitton (LVMH.PA) to show the Sewelo diamond, also from the Karowe Mine, with each of the three parties taking ownership. “We’ve been in the business for many years, for quite some time, and these types of things do get us excited because of the sheer size,” Oded Mansori, chief executive officer of HB Antwerp, told Reuters. He held up a hand, curling his fingers as if holding an egg, to demonstrate its size. The partners aim to throw the spotlight on the natural state of the stone, at a time when lab-grown diamonds are casting themselves as viable commercial alternatives to real diamonds. The mining company started using x-ray technology in 2015 to help locate and identify diamonds. "We do expect that we will recover more exceptional diamonds in excess of a thousand carats in size - but on a global basis, this is still an extremely rare and unusual event,” said Lucara"s chief executive, Eira Thomas.