Synonyms that are in the dictionary are marked in green. Synonyms that are not in the dictionary are marked in red.
Antonyms that are in the dictionary are marked in green. Antonyms that are not in the dictionary are marked in red.
While they do not drop Rupees, they do produce the similarly-crystalline Bubbul gems, which can then be traded to Koltin in exchange for various rewards (including the Mystic armor set, which notably causes Link to lose Rupees instead of hearts).
Source: https://screenrant.com/zelda-tears-kingdom-blupees-rupees-caves-tok/