Most new installations or new construction does NOT include sealing the stone.  This can also prove to be the most overlooked application process, as once done one cannot visually determine whether it was done or not.

The most basic test is to sprinkle some water onto the surface and let it sit for 15 to 30 minutes.  If the stone takes on a darker wet look it is not sealed.  A sealed surface will keep the water beaded up on the surface.