HOW DOES ONE KNOW WHETHER THE GRANITE IS CRACKED

HOW DOES ONE KNOW WHETHER THE GRANITE IS CRACKED OR HAS A FISSURE?

We had a granite countertop (three-quarter-inch thickness) installed last week and I noticed what I believe is a crack between the undermount sink and the front edge of the countertop -- a distance of about 5 inches.  The granite is Delacattus and has a waterfall edge, which consists of a second piece of granite, about two inches wide, glued to and set back slightly from the granite top.  The crack is through the thickness of the granite top, but has not affected the bottom layer of the waterfall edge.  The installer says this is a natural fissure in the stone.  However, I believe it is a crack because it is all the way through the granite and is very irregular in shape.  After I complained, the installer put a product he described as "like Crazy Glue" over the crack and rubbed it in.  He said it would penetrate through the granite.  It seems odd that a normal fissure would require a glue-like penetrating substance.  Based on this description, do you think the granite is cracked or that this is a normal fissure?

Thanks for your advice.

Len