Philadelphia - 5 to 10 oz Class Ingots
The United States Mint Philadelphia silver ingots in the 5 oz to 10 oz class pictured above are in Type order based on hallmark appearance by serial number as can be seen in the United States Mint Philadelphia Registry. The 5 oz to 10 oz class is actually the most common of all weight classes and make up over one half of the entire United States Mint Philadelphia Registry. Having said that, the fact that only 25 exist in the United States Mint Philadelphia Registry still makes them among the most rare United States Government silver ingots in existence.
Beginning at the left above, the hallmarks in order are Type I, Type II and Type III. The Type I hallmark appears on the lowest serial number I have seen to date; the Type III is the standard hallmark we see on other United States Government silver ingots into 1980 so the third example ends up falling in the middle as Type II.
There is a good bit of variety in shapes and sizes within the 5 oz to 10 oz class; apparently fragments were not beyond stamping. Among the standard like those pictured above, they measure 1.35 inches by 2.50 inches within tenths.
It is not uncommon to find multiple hallmarks on a single ingot with obverse and reverse not matching. Throughout the 5 oz to 10 oz class, fineness is always 999. Melt No. 10 appears on almost all ingots in this weight class as well.
Some other examples of the United States Mint Philadelphia silver ingots in the 5 oz to 10 oz class are pictured below.