Circle
To create a circle button use the circle modifier. Circles are
made to only contain icons.
Markup
<button pam-Button="circle">
    <i class="material-icons">add</i>
</button>
<button pam-Button="circle raised">
    <i class="material-icons">add</i>
</button>
<button pam-Button="circle outlined">
    <i class="material-icons">add</i>
</button>
<button pam-Button="circle flat">
    <i class="material-icons">add</i>
</button>