The worth of a United States twenty-five cent piece struck in 1964, composed of 90% silver and lacking a mint mark, is primarily dictated by its silver content. These coins, produced before the switch to clad coinage, hold intrinsic value beyond their face value due to the precious metal they contain. The absence of a mint mark indicates that it was produced at the Philadelphia Mint.
The significance of these particular coins lies in their historical context as the last year of silver coinage for general circulation in the United States. This, combined with the fluctuating price of silver, drives collector interest and determines the market value. Many individuals retain these coins as a tangible asset and hedge against economic uncertainty. Furthermore, its historical signifiance contributes to its worth, as it represents the end of an era in American coinage.