This tutorial is going to show you an icon theme called ieos7, which is based on Mac Mountain Lion.
This theme is created for Elementary OS Luna. I’ve tested it on Ubuntu 13.04 Raring Unity, and it works.
For Ubuntu 12.04 Precise and Elementary OS Luna, you can install this icons by running below 3 commands one by one in terminal (Ctrl+Alt+T):
sudo add-apt-repository ppa:elementary-br/projects sudo apt-get update sudo apt-get install ieos7-icons
For other Ubuntu editions, directly download and install the ieos7-icons DEB package from launchpad.net
Once installed, use Unity Tweak Tool, Gnome Tweak Tool or other system tools to apply the theme.