Phyllite|thumb
thumb|[[Photomicrograph of thin section of phyllite (in cross polarised light)]]
thumb|Fractured [[Duke_University#Duke_stone | Duke stone showing phyllitic texture]]
thumb|Phyllite
Phyllite ( ) is a type of foliated metamorphic rock formed from slate that is further metamorphosed so that very fine grained white mica achieves a preferred orientation. It is primarily composed of quartz, sericite mica, and chlorite.
Phyllite has fine-grained mica flakes, whereas slate has extremely fine mica flakes, and schist has large mica flakes, all mica flakes of which have achieved a preferred orientation. sericite, or chlorite, or the translucent fine-grained white mica,
Carolina "slate" is often volcanic phyllite. A type of Carolina slate, Duke stone, is a dacitic phyllite that is fractured and colored with iron oxide.