noun
clay mineral
Technical term in geology and soil science for hydrous aluminium phyllosilicate minerals that form clay.
この地層にはモンモリロナイトなどの粘土鉱物が多く含まれている。
This stratum contains many clay minerals such as montmorillonite.
粘土鉱物は水
Clay minerals have the property of swelling when they absorb water.