Gruen watches were designed and made first by Dietrich Gruen, a German watchmaker who came to the United States in 1867, and later by his son Fred. Early Gruen watches included pocket watches and wristwatches for men and women. Gruen watches were known for their elegant and thin design, marketed by the company as VeriThin. The American-based family-owned Gruen Watch Company closed in 1953, but Gruen watches were made in Switzerland until 1976. Today, the name Gruen is licensed to M.Z. Berger and Company, which continues to produce replicas of classic Gruen watches under the Gruen name.
Gruen watches made prior to 1976 are collectible items, and pre-World War II wristwatches are especially prized by collectors. Identifying a Gruen watch can be done by carefully examining several parts of the watch.
Look at the watch face. Gruen watches have the name “Gruen” on the face, usually just below the 12 at the top of the watch. Watches made after 1953 will say “Swiss” underneath “Gruen.” Watches missing the “Gruen” mark on the face or that have “Gruen” misspelled are not authentic.
Look on the back of the watch. Gruen watch backs may say “Gruen” and may also have the name of the watch style engraved on them. “SemiThin,” “VeriThin” and “UltraVeriThin” are all Gruen marks that may appear on the back of a Gruen watch.
Have a jeweler open the back of the watch case for you to look inside at the works. Gruen works are stamped with serial numbers indicating year of make. This may differ from the serial number on the case, so always look at the works for the number. Check your number against the table at http://www.pocketwatchrepair.com/histories/gruen.html to identify the year the watch was made.