The Gnostics and Their Remains, by Charles William King, [1887], at sacred-texts.com
THE drawings were, for the most part, made from gems in the Praun Cabinet, now transferred to the British Museum, some few from my own collection, now in the Museum of Art, New York. The materials are either dark green and yellow jaspers, or calcedonies varying in colour from olive green to light yellow. All designs are drawn to double the actual size.