Kim Kardashian's engagement ring has sold at auction for $749,000 (£499,000).

The Lorraine Schwartz rectangular-cut diamond sparkler, which the reality Tv star was given by her ex-husband Kris Humphries, went under the hammer at Christie's in New York on Tuesday (15Oct13), and was snapped up by an anonymous phone bidder.

The gem, which features a 16.21-carat centre diamond and two 1.8-carat side sparkling stones, was actually bought for $620,000 (£413,330). The mystery buyer will end up shelling out a total of $749,000 after fees, reports UsMagazine.com.

A portion of the proceeds are expected to be donated to charity.

Kardashian split from basketball player Humphries on 31 October, 2011 after just 72 days of marriage. They finalised their divorce in May (13), weeks before the Tv beauty gave birth to her first child with boyfriend Kanye West.