rarity

Something rare.

The quality or state of being rare; infrequency of occurrence.

The condition of being rare, or not dense, or of occupying, as a corporeal substance, much space with little matter; thinness; tenuity: opposed to density.

The state of being uncommon or of infrequent occurrence; uncommonness; infrequency.

Something that is rare or uncommon; a thing valued for its scarcity or for its unusual excellence.