(IDEX Online) - A collection of over 200 pieces of jewelry owned by George Schultz - former US secretary of state - and his philanthropist wife Charlotte are to be auctioned at Bonham's New York.Seventy of the items in Style and Substance: The Collection of George and Charlotte Shultz are by Tiffany & Co.Among the highlights are the Hedges and Rows platinum and gold necklace (pictured, detail) with 26.60 carats of round diamonds, accented by round cabochon turquoise flowers and 12 cushion-shaped yellow beryl (estimate $150,000 to $200,000).And a platinum, gold, emerald, sapphire and diamond Scarf necklace, with14.40 carats of diamonds (estimate $100,000 to $150,000). Both are by Schlumberger Studios for Tiffany & Co. Shultz was an economist, diplomat, and businessman, who served under three Republican presidents, including Ronald Reagan. He died in February 2021.He wed the heiress, socialite, and philanthropist Charlotte, nee Smith, in 1997. She died last December.The auction is on 23 May.