There are two completely different tunes (that I know of) called Diamond Joe, which appear to be unrelated.

The first one is a cowboy song. I first heard it from an Ian Tyson record back in the early 80s, but it’s a tune that has been kicking around for a long time. Here’s a fine version by Ramblin’ Jack Elliott from the Newport Folk Festival in 1963.

The other is an old time tune. Here’s Bruce Molsky…

Curiously, Bob Dylan has covered both tunes. Here he is doing the latter tune in the dreary Masked and Anonymous.

I believe Mr. Weird Bob covered the cowboy tune on his 1992 Good as I Been to You album, a strangely compelling collection of tunes that includes a delightful version of Froggie went a Courtin’, among other excellent selections.