What makes 1960 D penny valuable?

The 1960 D penny can be valuable primarily due to its minting characteristics, especially if it is a "small date" variety, which is much rarer than the "large date" version. Additionally, coins in Excellent condition, such as those graded by professional services, can command higher prices among collectors. The value can also be enhanced if the penny exhibits unique features like errors or unusual wear. Generally, the combination of rarity, condition, and demand among collectors determines its value.