Rarity (noun)

1. The state or quality of being rare; rarity.
2. Something that is rare or infrequent.

Origin:

From middle english, from old french rareté, from latin raritatem, from rarus ("rare").

Examples:

1. The coin's rarity makes it valuable.
2. The book is a rarity in the field of literature.
3. The snowfall was a rarity in that region.
4. The plant's rarity made it difficult to find.
5. The stamp is a rarity among collectors.