Washington Quarter History
The copper-nickel clad series of the Washington Quarter started in 1965, and as part of the switch Denver and San Francisco did not stamp their mint marks from 1965 to 1967 in any denomination. During the early 1960s, the Federal government had been flooding the market with silver to keep the price down, and therefore keep U.S. coins’ intrinsic values from passing their face values. However, this was causing the level of silver in the U.S. Reserves to reach dangerously low levels. Silver was estimated to only last another 3-5 years at the rate the Mint was manufacturing coins, so the U.S. Congress authorized the Mint to research alternative materials for the silver denominations (dime, quarter dollar, half dollar, and dollar). The material chosen was a 75% copper/ 25% nickel cupronickel alloy (identical to that in the five-cent coin) clad to a core of “commercially pure” (99.5%) copper.
For the first three years of clad production, in lieu of proof sets, specimen sets were specially sold as “Special Mint Sets” minted at the San Francisco mint in 1965, 1966, and 1967 (Deep Cameo versions of these coins are highly valued because of their rarity).
Currently, there are few examples in the clad series that are valued as highly as the silver series but there are certain extraordinary dates or variations. The Deep Cameo versions of proofs from 1965 to 1971 and 1981 Type Two are highly valued because of their scarcity, high grade examples of quarters from certain years of the 1980s (such as 1981–1987) because of scarcity in high grades due to high circulation and in 1982 and 1983 no mint sets were produced making it harder to find mint state examples, and any coin from 1981–1994 graded in MS67 is worth upwards of $1000.
The mint mark on the coin is located on the obverse at the bottom right hemisphere under the supposed date. In 1965–1967 cupro-nickel coins bore no mint mark; quarters minted in 1968–1979 were stamped with a “D” for the Denver mint, an “S” for the San Francisco mint (proof coins only), or blank for Philadelphia. Starting in 1980, the Philadelphia mint was allowed to add its mint mark to all coins except the one-cent piece. Twenty-five-cent pieces minted from 1980 onwards are stamped with “P” for the Philadelphia mint, “D” for the Denver mint, or “S” for San Francisco mint. Until 2012 the “S” mint mark was used only on proof coins, but beginning with the El Yunque (Puerto Rico) design in the America the Beautiful Quarters program, the U.S. Mint began selling (at a premium) uncirculated 40-coin rolls and 100-coin bags of quarters with the San Francisco mint mark. These coins were not included in the 2012 uncirculated sets or the three-coin ATB quarter sets (which consisted of an uncirculated “P” and “D” and proof “S” specimen) and no “S” mint-marked quarters are being released into circulation, so that mintages will be determined solely by direct demand for the “S” mint-marked coins.