Some Engelhard gold bars are so rare that our extensive research yields few results. After pouring over resource after resource, we were only able to find similar items. The back of this gold bar features an odd marking that was unidentifiable at first. After further research we discovered that this logo was likely a foundry mark that was never meant to be seen by the public. Of the similar weighted items that we found, all of them featured a Serial Number below the Engelhard hallmark. This leads the cataloger to believe that the Serial Number on the present bar may have worn off. Similar 1.608 oz gold bars were produced in 1967, but all of those are typically marked "0.9999" rather than "0.999". Needless to say, this particular bar has left your cataloger stumped. At the end of the day, we have no choice but to call this bar downright rare. PURITY: 0.999. MANUFACTURER: Engelhard.