Carroll Chatham perfected the process of growing emeralds in 1939, and in 1945 built the laboratory that John Chatham uses today to continue his father's work. The precious gems grown from Chatham Crystal's earth-friendly flux process are virtually identical to nature's own gems in all essential properties. Unlike many other manmade and natural gems, John Chatham's stones are never subjected to heat treatments, radiation or any type of color enhancement.