I will have to talk to the builder to see who they hired to do the
bathroom sinks. Don't know if warranty ran out, but if they can loosen
this drain, maybe it will help at least. Thanks for the info.


Those are stress cracks and they are usually caused by overtightening the
drain.

I don't know if they will get worse, but they shouldn't be there in the
first place.

G to this site and scroll down to the very last item.http://www.nhmarble.com/faq.html

Charlie