The 'Basic Instinct 2' star has always been open about her love for fur, and is often pictured adorning fur accessories, reports the Daily Mail.
At the request of one of the guests at the event, Stone auctioned her own necklace, which featured a feather-shaped pendant.
The necklace was sold for 50,000 US dollars.
Other celebs present at the event included film director Sofia Coppola, model Eva Herzigova and actress Mira Sorvino.
The benefit for the American Foundation for AIDS Research, or amfAR, was held on the sidelines of the Rome Film Festival.