TT #267 · Parshas Tazria · Aliyah 7 · Passuk 48
English: or in the warp or woof of linen or wool, or in leather or any article made of leather,
Sifra (Toras Kohanim).
English: The rule excludes unfinished hides that have not yet undergone the required processing.
Textual derivation
Leather that has not undergone the prescribed processing is not included in the garment-tzaraas category.