Font Awesome
             

fa-sort-amount-desc · Unicode: f161 · Created: v3.2 · Categories: Web Application Icons

After you get up and running, you can place Font Awesome icons just about anywhere with the <i> tag:

fa-sort-amount-desc 
<i class="fa fa-sort-amount-desc"></i> fa-sort-amount-desc

Looking for more? Check out the examples.