nobleness (n.)

"state or quality of being noble," c. 1400; see noble (adj.) + -ness.

In application to things nobleness is rather more appropriate than nobility, as the nobleness of architecture or one's English, while nobility is more likely to be applied to persons and their belongings, as nobility of character or of rank; but this distinction is no more than a tendency as yet. [Century Dictionary, 1895]