A special Barbie doll is about to go on sale.

The custom-designed doll is donning a necklace featuring a 1-carat pink diamond. She's being offered Oct. 20 at Christie's auction house in New York for an estimated $300,000 to $500,000. At that selling price, Christie's says she would be the world's most expensive Barbie.

All proceeds will benefit The Breast Cancer Research Foundation in support of Breast Cancer Awareness Month.

Jeweler Stefano Canturi arranged the emerald-cut, fancy vivid diamond in a geometric pattern with smaller white diamonds, totaling 3 carats. He also designed the doll's black strapless dress, stilettos, hair and other features.

The world auction record for a Barbie is $17,091, set in 2006 at Christie's London.