Learn something every day. Philip Anderson writes in rec.heraldry:
Maria is the Latinisation of Miriam, which means something like “drop of the ocean”. But the Latin translation of this, stilla maris, was confused with stella maris, i.e. “star of the sea”, which is said to be why she is often shown with a blue robe decorated with a star.
2004 Oct 24: Now it occurs to me that the same root is in distill and in carmine Burānō: Fortune plango vulnera / stillantibus ocellis (I bewail the wounds of fortune / with dripping eyes).