Kim Kardashian's engagement ring has sold at auction for nearly US$750,000 (NZ$896,000).

The platinum ring designed by Lorraine Schwartz, given to Kardashian by her ex-husband Kris Humphries, went under the hammer at Christie's in New York on Tuesday.

It was snapped up by an anonymous phone bidder.

The ring features a 16.21-carat centre diamond and two 1.8-carat side sparkling stones.


Bidding began at US$200,000 and quickly rose to $480,000. After a pause it went to $520,000. It then slowly climbed to reach a final bid of $620,000, reports Forbes magazine.

Commission and fees brought the price of the ring to $749,000.

Rahul Kadakia, head of Jewellery for Christie's Americas and Switzerland, who led the auction, announced that a portion of proceeds will benefit a charity.

Humphries, an NBA basketball player, paid a reported $2 million for the ring.

Kardashian split from Humphries on October 31, 2011, after just 72 days of marriage.

They finalised their divorce in May this year, just weeks before the TV reality star gave birth to daughter North with boyfriend Kanye West.