We’ve had this vanity installed in our bathroom for 5 months.  I absolutely LOVED IT!  However, it now appears that the adhesive or “something?” is discoloring the marble top.  I looked online for this type of issue with marble and found that water sitting on the vanity top for extended periods of time could stain the surface, but this stain is MUCH TOO DARK to be from water.  It almost looks like some type of colored adhesive or caulking was used on the underside of the under mounted sinks and that is now seeping into the marble, discoloring it from below.  I am going to contact Wayfair about this issue as this was NOT an inexpensive item.  Stay tuned,