The Collaborative International Dictionary of English v.0.48:

Pureness \Pure"ness\, n.
   The state of being pure (in any sense of the adjective).
   [1913 Webster]

WordNet (r) 3.0 (2006):

pureness
    n 1: being undiluted or unmixed with extraneous material [syn:
         purity, pureness] [ant: impureness, impurity]
    2: the state of being unsullied by sin or moral wrong; lacking a
       knowledge of evil [syn: purity, pureness, sinlessness,
       innocence, whiteness]
    3: a woman's virtue or chastity [syn: honor, honour,
       purity, pureness]