Here's how you can install the Ursa icon theme in Linux Mint 17. See the screenshot below to view a sample of the icons. They offer an attractive alternative to the default icon theme in Linux Mint. Please note, however, that they are still in beta so bear that in mind if decide to install them.
1. Open a terminal window.
2. Type in the following commands then hit Enter after each:
sudo add-apt-repository ppa:noobslab/icons
sudo apt-get update
sudo apt-get install ursa-icons
Source: Noobs Lab
Additional resources for Ursa Icons
Additional Linux Mint resources