Argillaceous minerals
（重定向自Argillaceous rock）
Argillaceous minerals may appear silvery upon optical reflection and are minerals containing substantial amounts of clay-like components (Greek:ἄργιλλος = clay). Argillaceous components are fine-grained (less than 2 µm) aluminosilicates, and more particularly clay minerals such as kaolinite, montmorillonite-smectite, illite, and chlorite. Claystone and shales are thus predominantly argillaceous.