Custom Cursor Image CSS
Your problem may be that cursor URLs don't work in Firefox for the Mac.
You can get the same effect on Firefox by using the -moz-zoom-in keyword.
cursor:url(/img/magnify.cur), -moz-zoom-in, auto;
This will show magnify.cur, the Mozilla-specific zoom cursor or a system default cursor. The first cursor on the list that the browser supports is used.
You can also see a list of cursor keywords supported by different browsers.
This did the trick :)
a.heroshot img {
cursor:url(/img/layout/backgrounds/moz-zoom.gif), -moz-zoom-in;
}