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A metamorphic rock intermediate in grade between slate and schist, and derived from argillaceous sediments; has a silky sheen on the cleavage surface.



a metamorphic rock that consists mainly of minute flakes of sericite or chlorite and is characterized by a fine schistosity. Phyllite also contains grains of detrital quartz and sometimes contains protogenous albite crystals. Phyllite is usually dark gray or black. It is formed during low-grade regional metamorphism of predominantly argillaceous sediments and is intermediate in metamorphic grade between clay slate and mica schist. (See alsoSLANTSY.)

References in periodicals archive ?
The targets at Arabia include vein swarms exposed in a window, approximately 1 kilometer by 2 kilometers in dimension, bounded by post-mineral volcanic cover on the west, south and east and by phyllitic country rock to the north.
Felsic to intermediate volcanic clasts are most common; however, these clasts commonly show some phyllitic foliation, which is quite distinct from primary banding or fragment alignment, which are also visible in some clasts.
The country rocks consist mainly of quartz-garnet-biotite schists, phyllitic schists, epidote-bearing quartzites, and graphitic schists (Sharpe, 1962; Charles, 1985) of the Kuiseb Formation (Khomas Subgroup, Damara Supergroup).
4 kilometer area of strong gossan developed in quartz-sericite altered granite and phyllitic country rock.
Quartzite layers acted competently, whereas phyllitic layers were more ductile.
The mine itself is situated in a siliceous phyllitic unit, very near a major fault contact with serpentinized peridotite [ILLUSTRATION FOR FIGURE 3 OMITTED].
The K9 claims cover a steeply dipping package of phyllitic quartzites and dolomitic limestones belonging to the Proterozoic Creston and Kitchener Formations.
11) of grey-green to rusty phyllitic quartzite or meta-volcaniclastic siltstone similar to the major lithology of the Ingalls Head Formation to the east (Fig.
The Seravezza marbles are located along the southern boundary between the Massa Unit and the phyllitic Paleozoic basement, which hosts the main sulfide mineralization of the Apuan Alps (Carmignani and Giglia, 1975).
Along strike to the southwest where regional metamorphism is at biotite and garnet grade, the metasiltstone is more phyllitic to schistose and light greyish-green.
Drill holes OM 001 and OM 002 intersected alternating zones of altered diorite porphyry, mineralised contact breccia zones, and phyllitic metasediments.