Mike,
I can only assume it was "Sambuca" you were drinking. It
is a clear liqueur originating from Italy with a distinctive aniseed taste
(quite refreshing).
I have seen a mint-flavoured variation, but it is green. If this was actually
a mixed cocktail, it may
have been performed by adding some clear Creme de Menthe to Sambuca.
The tradition of floating three coffee beans on top is meant to bring good
luck - the liqueur is
often flamed before serving, which gives an additional 'roast' to the beans,
imparting a mild
coffee aroma as you drink the liqueur.
Hope this has been of help - Cheers!
Damian