J. KNEWITZ Höfchen 4, Mainz http://www.925-1000.com/td/f/Germany_Austria/Knewitz-1927.jpg J. Knewitz - Mainz - 1927 Established in 1834 by Jakob Knewitz, this family-owned firm is still in business today. Jakob's son, Fritz, ...
The mark KW stands for Wilhelm Knewitz. In my source is written J. Knewitz what means Juwelier Knewitz. The present owner of Knewitz, Mainz (5th generation) Rainer Knewitz told me, that there was also a jeweller Jakob Knewitz (first generation), ...