The icon pack can be installed on an assortment of Linux distros, not just Ubuntu
The Numix Project has issued its tenth upgrade for the Numix-Circle Linux Desktop Icon Theme, and it features a lot of application icons.This Numix-Circle theme has been updated and, according to its designer, it uses circle-shaped application icons. The icon pack has been getting more and more icons, and the number of supported applications is now well over 600.
The theme contains Folders icons, System Settings icons, Indicator icons, Symbolic icons, and a lot more. With so many supported apps, it's hard not to find everything you might need.
There are virtually no other icon packs that provide rounded icons and the Numix-Circle Linux Desktop Icon Theme will definitely make your system quite unique.
The team also provides an easy way to install and test the new icon set, although it's not finished yet and more updates will be provided. Just open a terminal and enter the following commands:
sudo apt-add-repository ppa:numix/ppa
sudo apt-get update
sudo apt-get install numix-icon-theme-circle
You will also need GNOME Tweak Tool or some other application to change the icons, but it is totally worth your while. If GNOME Tweak Tool doesn't work (it has some issues with the latest Ubuntu 14.04), you can try Unity Tweak Tool.