I agree that "super carbon" versus "diamond" are ambiguous marketing terms. First of all, carbon is usually in two states, diamond or graphite. I am assuming that they are not using graphite in the balls, so the diamond would be the one they are using. But, diamonds would be much too hard or have to be in a very small amount in the coverstock, so i am assuming it is some sort of plastic compound that happens to have carbon on there and when everyone hears carbon, they think of "carbon steel" which is supposedly "better" steel. For this reason, the marketing directors decided to add "carbon," kind of like how other companies add random numbers and letters to make them sound hi-tech.
There may be diamond particles in the legends balls, but the percentage would have to be very small and they would have to be very very tiny or else they would create a coverstock much too hard. For this reason, i really doubt those particles are much different or last any longer than other particles.
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stanski