Program aims to educate young consumers about mined stones’ positive qualities.
Lot featuring two 5.01-carat stones will carry a $304,000 high estimate at the May 14 auction.
A Cartier ruby ring sells for $560,000, more than eight times its high estimate.
Lot had estimate of $1.5 million at December 11 sale, which totaled $11.8 million.
Sapphire and diamond ring nearly triples estimate to become top seller at $819,982.
Piece expected to bring in up to $704,750 at Sotheby's.
Lot consisting of necklace, bracelet, earrings and ring has high estimate of $231,000.
All items on offer found buyers, with 60% fetching above high estimates.
Emerald-cut, 8.02-carat diamond is top seller, at $215,900.
Top lot was Sabbadini diamond ring that more than doubled its high estimate.