"Ln" in cursive stands for "Laurin" and was introduced around 1936 as a seal of approval for mid-priced jewelry. In the "Watchmaker Week" No. 23 of 1936, the reasons for the introduction are explained: The jewelry industry apparently suffered from a "lack of buying" and sought a way to "boost" the business. It was found that buyers of mid-priced jewelry had little opportunity to test the quality of the product. The Laurin mark therefore served as a guarantee of the quality and authenticity of the materials used. It was not tied to specific manufacturers. The mark was sponsored by Association of wholesalers of the precious metals trade. (Verband der Grossisten des Edelmetallgewerbes e.V.) The mark disappeared completely by the end of WW II.
Hello, the Laurin mark was probably introduced a little earlier than 1936, still trying to find out the exact date though. Use of the pictorial mark (Ln ligated in a half circle) was disabandoned at the end of WW II, Laurin as a word was again registered as a trademark for jewellery in 1961 by maker Fritz Voegele from Pforzheim. Looks like he might still be active. Regards Bahner