Exceptional Marcus &amp; Co. Colombian Emerald Gold Ring. Simply Breathtaking Colombian emerald gold ring attributed to a linage American jeweler Marcus &amp; Co.. This 1900s treasure centers on a bright and glowing translucent green cabochon emerald, weighing approximately 4.3 ct, which makes this precious ring exceptional. The beautifully textured Art Nouveau style mount showcases the height of the American Art Nouveau style which distinguishes the renowned jeweler. c 1900