This sherd comes from a brown salt-glazed, stoneware ‘Selters’ water bottle, and most likely dates between 1830-1870.  Produced in the Duchy of Nassau in western Germany (‘Herzogthum Nassau’ as visible on the seal), these bottles contained Selters mineral water that originated from the springs on the slopes of the Taunus Mountains. By the mid 18th century this water was shipped all over Europe in bottles such as this, and became so famous that when artificial carbonation was invented, such products eventually became known as ‘Seltzer water’ as they still are today.