Clash of the diamond towers

From left: Extell’s International Gem Tower, Gary Barnett and 580 Fifth Avenue

Construction on Extell Development’s 34-story International Gem Tower condominium, on West 47th Street between Fifth and Sixth avenues, is on hold until Jan. 1, when Extell says it will “go vertical,” the New York Post reported. Meanwhile, 580 Fifth Avenue at the corner of 47th Street, is vying to be the center of the global diamond trade. Though Extell’s tower was recently approved as a Foreign Trade Zone by the U.S. Department of Commerce, 580 Fifth Avenue — at 400,000 square feet — is 95 percent leased, while the Gem Tower’s 750,000 square feet remain frozen at sidewalk level. In its condo filing with the state attorney general in January 2009, Extell said its tower would be “substantially complete” by October 2010. Asking rents at 580 Fifth Avenue, known as World Diamond Tower, are “in the $50s a square foot,” said Ken Kahn, a part-owner who is also one of the building’s executive managers. However, several of Kahn’s major tenants have signed contracts with Extell’s Gary Barnett to move to the Gem Tower, including the Gemological Institute of America, which has a contract to buy a full floor. [Post]