Program aims to educate young consumers about mined stones’ positive qualities.
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.
London Jewels auction will also feature several single-owner collections.
Designer created “Sabi” finish, a Japanese-inspired gold technique.
Diamonds dominate top 10 lots of December 6 Important Jewelry sale.
17.61-carat blue stone is most expensive sold at auction this year.
Featuring emerald-cut, 13.84-carat diamond, the piece fetched $699,000 at New York auction.
Ring featuring pear-shaped, 8.38-carat stone is top item.
Lifting of travel restrictions drove 11% sales growth in first half.
Kashmir sapphire weighing 7.58 carats fetches $1 million — more than double its upper estimate.