Text gradient with font awesome

Solution 1:

Gave this a quick shot; the important thing to realize is that Font Awesome adds the actual icons via the 'before' pseudo-element:

[class^="icon-"]::before,
[class*=" icon-"]::before {
  font-family: FontAwesome;
  font-weight: normal;
  font-style: normal;
  display: inline-block;
  text-decoration: inherit;
}

.icon-beaker:before {
  content: "\f0c3";
}

To apply the gradient-effect to the icon, you have to target the pseudo-element which contains the icon – see this jsFiddle for a working demonstration based upon your code:

.big-icon:before {
  font-size: 72px;
  background: -webkit-gradient(linear, left top, left bottom, from(#f00), to(#333));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: initial; /* reset Font Awesome's display:inline-block */
}​

Edit: The jsFiddle linked above does not work as expected anymore because the linked CSS-file that contains the "FontAwesome"-icons has moved; a working version using the bootstrapcdn.com-hosted version of FontAwesome v4.0.3 and updated FontAwesome-icon CSS class names is available at http://jsfiddle.net/HGxMu/55/

Solution 2:

Apply the styles directly on the icon.

.fa-gradient {
	background: -webkit-gradient(linear, left top, left bottom, from(#f00), to(#333));
	-webkit-background-clip: text;
	-webkit-text-fill-color: transparent;
}

<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet"/>
<i class="fa fa-3x fa-wrench fa-gradient"></i>