FILE PHOTO: Signage is seen outside the Blackstone Group headquarters in New York City, U.S., January 18, 2023. REUTERS/Jeenah Moon MUMBAI :Private equity company Blackstone Inc said it has fully acquired the jewellery certification firm International Gemological Institute (IGI) from China's Fosun and the company's founding family. Blackstone bought IGI, whose majority revenue and profits come from India, for about $530 million, a person with direct knowledge of the matter said on condition of anonymity. A statement said Blackstone had purchased an 80 per cent stake from Fosun and 20 per cent from the Lorie family.