Another useful post from another thread.
I'll do my best on this one. Let's start with the timeline first.
I believe Black was first, followed by Red, then Blue, then Red Pearl, then Blue Pearl, then Pink, then Purple, and finally Burgundy. So in reverse:
Burgundy: roughly 1994.
Purple: 1993.
Blue Pearl: 1990?
Red Pearl: 1991?
Pink: 1989.
Blue: 1988.
Red: 1987.
Black: 1986 or older.
Before then, the Nail was all over the place.
Now, specs of the balls. From strongest to weakest, the lineup went:
Burgundy - Blue - Purple - Black - Red - Red Pearl - Blue Pearl - Pink.
The difference between all of these balls were coverstock and coverstock preparation. "Pearl" in the name is obvious. The Pink Hammer was the weakest in coverstock preparation, whereas the Burgundy was the strongest. The Blue hammer was (I believe 800 grit abralon), so you can take a good guess at where Burgundy was.
Each of the Fab Urethane Hammers had the same core, so it all came down to the coverstock.