rarity

rarity (http://definr.com/rarity)

     n 1: noteworthy scarcity [syn: rareness, infrequency]
     2: a rarified quality: "the tenuity of the upper atmosphere"
        [syn: tenuity, low density]
     3: something unusual -- perhaps worthy of collecting [syn: curio,
         curiosity, oddity, oddment, peculiarity]