Making Moderns column from Sept. 12, 2016, weekly issue of Coin World:

The first copper-nickel clad half dollars were struck in 1971, with 155 million coined at the Philadelphia Mint and a series high 302 million at the Denver Mint. They were saved in roll quantity, and intact original rolls can still be found today. As a result, coins grading Gem Uncirculated are relatively abundant. 

This description “Gem Uncircu­lated” is widely used to describe superior quality coins that were never used in commerce. It accords to Mint State 65 on the numerical grading scale used by the grading services.

Coins graded MS-65 will have full luster, few contact marks especially in focal areas and above average strike. It is this last feature — strike — that is the most variable among Gem Uncirculated half dollars of the 1970s and 1980s.

Desirous of getting as many copper-nickel clad half dollars into commerce as possible, the Mint accelerated production. In 1970, the U.S. Mint struck only 2 million half dollars, all at the Denver Mint. The Denver Mint increased that number by 150 times in the following year. 

Each set of dies was used to strike coins as long as possible, exceeding 200,000 coins per die pair. During use, dies wear and fatigue. Over time, the heat and pressure of coinage production distort and soften detail in dies; the coins they strike can be flat, with mushy or even absent detail.

Well-used dies, called late die state, can also impart an irregular texture to a coin’s fields. In extreme cases, at the periphery, legends become faint and fade into the rim.

Illustrated here are the obverses of two 1971-D half dollars, both graded MS-66. One is from relatively fresh dies. Its smooth, glossy surface and crisp detail are the markers of early die state. Note the hair detail, and sharpness of the letters. 

The other is from late state dies. Much of the hair detail, from Kennedy’s temple to crown, is worn away. A pebbly texture is visible in the fields and on the neck. One the reverse, the shield merges into the eagle’s neck, which lacks feather detail entirely. 

Because the latter coin is essentially free of marks, has a wonderful, original surface and full luster, the MS-66 grade is very appropriate. In fact, it is fully struck, just from late state dies.

Nonetheless, its soft appearance makes it less desirable; it traded in auction for a very modest $11. The comparable example from new dies traded for a robust $33. 

NGC price guide for the 1971-D Kennedy half dollar in MS-66 is $28.