Overwriting equation labels

Suppose an equation would be labelled automatically by latex as (3.1) (or or something similar), but, for whatever reason, you'd like to label it by a different name. For example you might want to label it (*). How is this possible? And if this isn't possible, then can you manually do something to make it appear like a label? What I mean is, can you write your equation and then right align something like " (*) " ? I can't seem to do this without messing up the spacing of the equation itself. Thanks for any help!