Christie's Twentieth-Century Jewelry
David Lancaster is a director of Christie's South Kensington and head  of the jewelry department. He is a fellow of the Gemological Association, earned  the Diamond Diploma from the Gemological Institute of America, and is a  committee member of the Society of Jewelry Historians. Sally Everitt is a  specialist in the jewelry department of Christie's South Kensington. She sits on  the Members Council of the Gemological Association and is the examiner for the  jewelry section of the Royal Institute of Chartered Surveyors in the UK. David  Lancaster and Sally Everitt live in Hertfordshire, just north of London.