noun
paper slate
Technical term in mineralogy for a type of slate that splits into thin, paper-like sheets.
この地域の紙石盤は屋根材として使われていた。
The paper slate from this region was used as roofing material.
Compound of 紙 (kami, 'paper') and 石盤 (sekiban, 'slate'), referring to its thin, paper-like cleavage.