Here's how you can install the Ardis icon theme in Linux Mint 17. This icon set is currently in beta so bear that in mind if you install them. See the screenshot below to see what they look like, I really like the way they look compared to the default Linux Mint icon set.
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 ardis-icons
Source: Noobs Lab
Additional resources for Ardis Icons
Additional Linux Mint resources