(DDO) 1950-D/S Over mintmark (coin is a 1950-D, with underlying S mintmark) 1950-S/D Over mintmark (coin is a 1950-S, with underlying D mintmark) The 1940-D, 1936-D and the 1935-D coins, as well as many others in the series, are considerably more valuable than other quarters. This is not due to their mintages, but rather because they are harder to find in high grades (a situation referred to as "condition rarity"). Many of these coins are worth only melt value in low grades. Other coins in the above list are expensive because of their extremely low mintages, such as the 1932 Denver and San Francisco issues. The overstruck mintmark issues are also scarce and expensive, especially in the higher grades; even so they may not have the same popularity as overdates found in pre-Washington quarter series. The 1934 Philadelphia strike appears in two versions: one with a light motto [for "In God We Trust"], which is the same as that used on the 1932 strikings, and the other a heavy motto seen after the dies were reworked. Except in the highest grades, the difference in value between the two is minor. The mint mark on the coin is located on the reverse beneath the wreath on which the eagle is perched, and will either carry the mint mark "D" for the Denver Mint, "S" for the San Francisco Mint, or be blank if minted at the Philadelphia Mint. Collecting clad Washington quarters The copper-nickel clad Washington quarter was first issued in 1965 and as part of the switch, the Denver mintmark was added in 1968, which did not reappear on any US coin denomination until 1968. 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 2 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