First 1864 bronze cents were really made of bronze 0

[RWB]

This is the first assay of French Bronze used for US one-cent coinage in 1864. The alloy indicates it really is bronze - more tin than zinc - and not the brass alloy used later where zinc predominated.

Edited December 5, 2020 by RWB

[DWLange]

By the 20th Century it appears that there was rarely more than 1% of tin in cents, and this was merely to comply with the law that 5% of the alloy be a mix of tin and zinc. Eliminating it altogether during 1944-46 doesn't seem to have had any effect on the coins' striking quality, appearance or utility, and the final removal of tin was formalized in 1962. At that point the coins no longer met the definition of bronze and were brass until 1982.

[RWB]

Reduction of tin to a "trace" began after May 1941 and continued until the formal change in 1962....not that anyone paid much attention.

The bronze assay tables are being extracted from Mint documents for general information and to aid counterfeit detection via careful XRF measurements. Modern fakes of early bronze 1-cent and 2-cent pieces will likely have an incorrect alloy. Presently, I have bronze assays #1-11 for 1864. The planchets came from Waterbury, CT.