When you click on the download area from Phalcon's website, it shows you a tab for Linux / Unix / Mac, but don't explicitly tell you which code you should use for Mac OSX.
Also, when you try a search on Google it gives you this page but when you try to run any of the brew codes it returns error with this message:
Error: No available formula for php54-phalcon
There should be an easier guide to install Phalcon on Mac OSX, just like there is for Windows or Ubuntu, for example.