vein or a crack

Hi !  We just had granite countertops installed (Super Classico from Brazil).  The stone is veiny, but there is one long "crack" about 32" long 3" from the edge of the counter.  It is very difficult to tell whether this is a vein or a crack.  It can be felt, but so can some of the more natural looking veins.  We viewed one of the two slabs used for the job, but may have missed this.  Is there any way to tell if this is damage caused by the fabricator?