Silver hallmarks - Wikipedia
https://en.wikipedia.org/wiki/Silver_hallmarksIn the early United States, no national assaying system was adopted, although the city of Baltimore did maintain its own assay office between 1814 and 1830. Prior to the general adoption of sterling silver as the standard of purity in 1868, silver was generally obtained from the melting of coins. Since these could vary considerably in purity, from around .750 millesimal fineness to around .900, silver known as "coin silver" varies in purity. Silver at that time was sometimes marked "COIN" or "…
Online Encyclopedia of Silver Marks, Hallmarks & Makers' Marks
www.925-1000.com925-1000.com is the most extensive internet resource for research of Silver Marks, Hallmarks, Trademarks & Maker's Marks found on Antique and Vintage silver. The site's main focus is the silver markings used on vintage and antique sterling and coin silver, for those of you interested in silverplate trademarks, we have now added a large section ...