Icons used for inline toolbars on GNOME applications?

[Chandler Paul <thatslyude gmail com>]

Hi, recently I've been working on making another GTK+ IRC client and
I've been trying to design one of the settings dialogs for it, which
happens to require an in-line toolbar for a GtkTreeView I have in it.
I'm having trouble figuring out how to get the icons to match those of
the default icons used by most GNOME applications in their in-line
toolbars (examples attached). Is there a certain style or option I
have to apply to achieve this, or are these a separate pack of icons
being used by GNOME?