These three Copper-Nickel coins (1960, 1972, 1974 Hong-Kong dollars) came my way free, and when I looked at the edges I was puzzled at the different edge treatment of the 1960. Wikipedia says the series, which began in 1960, has a 'reeded' edge. I'm familiar with reeding as looking like the 1972 & 1974...and recognize the detail in the 1960 as probably more difficult to counterfeit. First: what is the edge treatment of the 1960 called? And second: what's the truth about the difference in this series? Have I got something special? Thanks!
That $1 coin came in two types. The earlier one, dated 1960 or 1970, had a "security edge"; the later one, 1971-75, had a milled edge. By the way, that also applies to other denominations from those years: This security edge (don't know if there is a better term; that is what catalogs use) was used for 5c, 10c, 50c and $1 coins between 1955 and 1970. The milled edge was used between 1971 and 1980. Christian