For future reference, take a look at the _font-awesome.scss (or similar) file and you will see a list of all the icons created by the styles to facilitate the use of the font-awesome icon fonts. These are just prerolled for us but if you need a new icon that has been added to font-awesome, you will need to add it to this list (or one of your own making). You will notice that the icon is actually specified with the content attribute. For example, the lemon icon CSS looks as follows:
. icon-lemon:before { content: "\f094"; }This is because the icon is specified with the Unicode character F094. You can look this up at http://fortawesome.github.io/Font-Awesome/icons/. Just click on each icon to get to know a little more about each one.
While we're here, let's take a quick look at what else is going on to support these icon fonts. At the top of the _font-awesome.scss sheet, you will see that anything that has a class beginning with icon- gets some style by default...