(IDEX Online) - A Jacob & Co. watch owned by rapper Jay-Z sold for $1.5m at a charity event to help ex-prisoners.The white gold Caviar Tourbillon World Timer's dial and bracelet are set with 498 baguette diamonds, with a total weight of 35.52 carats. It keeps time in 25 cities.Jay-Z donated the timepiece for a star-studded casino night and auction in Atlantic City, New Jersey, USA, that raised a total of $24m. It was bought by an unnamed collector.All proceeds from the event went to the Reform Alliance, a charity he co-founded to get ex-offenders back to work and to push for legislation to transform probation and parole. Pic courtesy Jacob & Co.