Take your icon game to the next level. Check out Fonticons, from the maker of Font Awesome.
             

fa-envelope · Unicode: f0e0 · Created: v2.0 - email - e-mail - letter - support - mail - notification · Categories: Web Application Icons

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

fa-envelope
<i class="fa fa-envelope"></i>

Looking for more? Check out the examples.