Program aims to educate young consumers about mined stones’ positive qualities.
Auction features Van Cleef Zip necklace as well as Cartier Panthère and Bulgari Serpenti jewels among its more than 220 items.
Sapphire and diamond ring is top seller, surpassing its high estimate.
Here are the rough and polished stones that made for a memorable year.
Patek Philippe and Rolex pieces tie for spot.
Emerald-cut, 8.02-carat diamond is top seller, at $215,900.
Auction also sees strong demand for collections from Hollywood legends Mary Tyler Moore, Barbara Sinatra and Tony Randall.
Unmounted stone has a high presale estimate of $5 million.
Ring with 103.62-carat yellow diamond leads sale at $2.5 million.
Auction house sells more than 200 pieces in Geneva for nearly double their expected total.
Timepiece by renowned horologists George Daniels and Roger Smith leads Sotheby’s Geneva auction.