Probably the Caliber Junghans J58 and the Caliber J59 are no In-house caliber. They were pretty sure made by Felsa S.A., Grenchen, Switzerland.
The little sister of the Junghans J59. Here in the version with 15 stones, the anchor pallets are bright rubies (saphire). Not infrequently, the visible jewels were provided with red rubies and the invisible on the dial side were white.
These early wristwatches were produced at a time with a certain shortage of materials. The rubies were even then already manufactured industrially (so-called synthetic rubies). The colorless stones are (to my knowledge) called Saphire. If there was added chromium during the manufacturing process, the stone turns red, becoming the Rubin.
Another watch from the collection Bütow, with many thanks!
This watch has only 7 Jewels. On the case back there is the original protective film. The watch is near NOS. On the film is the imprint: RW with anchor (Rodi und Wienenberger (ROWI) case manufacturer; Pforzheim; Germany);
RW is also embossed in the case. Below is embossed: Walzgold doublé; 20 Mikrons; below is the Junghans star (8 pointed star) with J inside and "unghans" around.