This is the 3730th most frequent German word.
rares
"Rares" in German means "something rare" or "rarity."
Here, 'rares' is an adjective describing the noun 'book', indicating its rarity.
Ich habe ein rares Buch gefunden.
I found a rare book.
In this sentence, 'rares' is used as a noun to stand for rare items collectively.
Rares ist heute schwer zu finden.
Rare things are hard to find today.
'Rares' functions as an adjective in this sentence, qualifying 'artworks' to emphasize their uncommon nature.