| Diameter |
| 1858 – 1920: 25.40mm 1920 – 1979: 19.05mm 1980 – 1981: 19mm 1982 – 1996: 19.1mm (12 sided) 1997 – 2012: 19.05mm |
| Weight |
| 1858 – 1920: 5.67g 1920 – 1979: 3.24g 1980 – 1981: 2.80g 1982 – 1996: 2.50g 1997 – 2012: 2.25g 2001 – 2012: 2.35g (magnetic) |
| Composition |
| 1858 – 1919: .95 copper, .04 tin, .01 zinc 1919 – 1942: .955 copper, 0.30 tin, 0.15 tin 1942 – 1996: .980 copper, .005 tin, .015 zinc 1997 – 2012: Copper plated zinc 2001 – 2012: .940 steel, .045 copper, .015 nickel (magnetic) |