From mountain belts and road cuts to garden stones and building façades, metamorphic rocks are the record of pressure, heat and changing environments. They show how sediments and igneous bodies were reworked deep in the crust, and you can spot many common examples without specialized gear.
There are 50 Metamorphic Rocks, ranging from Amphibolite to Steatite. For each entry the data are organized with Category, Protolith, Grade & key minerals so you can compare origin, texture and mineralogy at a glance — you’ll find those details below.
How can I tell common metamorphic rocks apart in the field?
Look for texture (foliated vs non‑foliated), grain size, and key minerals: mica and schistosity suggest schist; banding and alternating composition point to gneiss; a crystalline, sugary feel and acid reaction indicate marble; a very hard, granular rock likely quartzite. Use a hand lens, a hardness check, and a drop of dilute acid to narrow options quickly.
Why does the list span from Amphibolite to Steatite?
That range reflects different protoliths and metamorphic conditions: Amphibolite represents higher‑grade, mafic‑derived rocks with amphibole minerals, while steatite (talc‑rich soapstone) comes from low‑grade alteration of ultramafic or magnesium‑rich rocks—showing the variety of pressure‑temperature and fluid histories captured in metamorphism.
Metamorphic Rocks
| Name | Category | Protolith | Grade & key minerals |
|---|---|---|---|
| Slate | Foliated | Shale or clay-rich sediment | Low grade; chlorite, muscovite, quartz |
| Phyllite | Foliated | Shale or mudstone | Low–medium grade; sericite, chlorite, quartz |
| Mica Schist | Foliated | Pelite (mudstone/shale) | Medium grade; biotite, muscovite, quartz |
| Garnet Schist | Foliated | Pelite or greywacke | Medium grade; garnet, staurolite, mica |
| Chlorite Schist | Foliated | Mafic volcanic rock or pelite | Low–medium grade; chlorite, muscovite, actinolite |
| Greenschist | Foliated | Mafic volcanic rocks | Low–medium grade; chlorite, actinolite, epidote |
| Amphibolite | Non-foliated | Mafic igneous rock (basalt/gabbro) | Medium–high grade; hornblende, plagioclase, garnet sometimes |
| Hornblende Schist | Foliated | Mafic volcanic rock | Medium grade; hornblende, plagioclase, biotite |
| Gneiss | Foliated | Pelite or granite protoliths | High grade; feldspar, quartz, biotite (banded) |
| Orthogneiss | Foliated | Metamorphosed igneous rock (granite) | High grade; feldspar, quartz, biotite |
| Paragneiss | Foliated | Metamorphosed sedimentary rocks | High grade; quartz, feldspar, mica, garnet sometimes |
| Migmatite | Foliated/Non-foliated | High-grade gneiss/pelite | Very high grade; partial melt, quartz, feldspar, biotite |
| Granulite | Foliated/Non-foliated | Various igneous/sedimentary protoliths | High grade; pyroxene, plagioclase, garnet |
| Quartzite | Non-foliated | Quartz-rich sandstone | Low–high grade; quartz, minor mica |
| Marble | Non-foliated | Limestone or dolostone | Low–high grade; calcite or dolomite, mica occasionally |
| Dolomitic Marble | Non-foliated | Dolostone | Low–high grade; dolomite, calcite, accessory minerals |
| Hornfels | Non-foliated | Claystone, siltstone, carbonate near intrusions | Contact metamorphism; pyroxene, garnet, mica, vesuvianite |
| Skarn | Non-foliated | Limestone or dolostone altered by intrusions | Contact metasomatism; garnet, pyroxene, wollastonite |
| Soapstone | Non-foliated | Mafic/ultramafic protoliths or dolomite | Low–medium grade; talc, chlorite, magnesite |
| Steatite | Non-foliated | Same as soapstone | Low–medium grade; talc, chlorite, magnesite |
| Serpentinite | Non-foliated | Peridotite or other ultramafic rock | Low–medium grade; serpentine group minerals, magnetite |
| Eclogite | Non-foliated | Basaltic or gabbroic protoliths | High pressure; omphacite, garnet, pyroxene |
| Blueschist | Foliated/Non-foliated | Mafic volcanic rocks | High pressure, low temperature; glaucophane, lawsonite, epidote |
| Greenschist-facies Metabasalt | Foliated | Basalt | Low–medium grade; chlorite, actinolite, epidote |
| Calc-silicate Rock | Non-foliated | Limestone with silicate input | Contact/regional; diopside, wollastonite, garnet |
| Metaconglomerate | Non-foliated | Conglomerate | Low–high grade; recrystallized clasts, quartz, feldspar |
| Metasiltstone | Foliated | Siltstone or mudstone | Low–medium grade; quartz, muscovite, chlorite |
| Metapelite | Foliated | Mudstone/shale rich in clay | Low–high grade; mica, garnet, staurolite |
| Meta-arkose | Non-foliated | Arkosic sandstone (feldspar-rich) | Low–medium grade; quartz, altered feldspar, mica |
| Quartz-mica Schist | Foliated | Sandstone or pelite | Medium grade; quartz, muscovite, biotite |
| Graphite Schist | Foliated | Carbon-rich sediments | Medium grade; graphite, mica, quartz |
| Pyroxene Hornfels | Non-foliated | Basalt or mafic protolith | Contact metamorphism; pyroxene, plagioclase, garnet |
| Calcite Marble | Non-foliated | Limestone | Varied grade; calcite dominant, dolomite minor |
| Dolostone Marble | Non-foliated | Dolostone | Varied grade; dolomite, calcite |
| Hornblende Gneiss | Foliated | Volcanic or plutonic mafic rocks | High grade; hornblende, plagioclase, biotite |
| Skarnified Limestone | Non-foliated | Impure limestone near intrusion | Contact metasomatism; garnet, pyroxene, wollastonite |
| Rocksilk (Silicified Hornfels) | Non-foliated | Various protoliths near intrusions | Contact metamorphism; quartz, microcrystalline silica |
| Hornblendite (metamorphic) | Non-foliated | Mafic protoliths | High grade; hornblende-dominant |
| Serpentinized Peridotite | Non-foliated | Peridotite | Low grade; serpentine minerals, magnetite |
| Anthracite | Non-foliated | Bituminous coal | High grade; carbon, minor quartz, trace sulfides |
| Mylonite | Foliated | Various protoliths in shear zones | Dynamic recrystallization; fine-grained quartz, feldspar, mica |
| Phyllonite | Foliated | Mylonized pelitic rocks | Dynamic recrystallization; mica, chlorite, quartz |
| Calcite Schist | Foliated | Calcareous mudstone or limestone | Medium grade; calcite, mica, chlorite |
| Hornfelsified Shale | Non-foliated | Shale near intrusions | Contact metamorphism; biotite, cordierite, andalusite |
| Calc-silicate Hornfels | Non-foliated | Impure carbonate sediments | Contact metamorphism; diopside, wollastonite, garnet |
| Rhyolite-derived Schist | Foliated | Rhyolitic volcanic rock | Medium grade; quartz, feldspar, sericite |
| Metabauxite | Non-foliated | Bauxite (aluminum ore) | Low–medium grade; gibbsite, boehmite, hematite |
| Metachert | Non-foliated | Chert or siliceous sediment | Low–high grade; microcrystalline quartz, chalcedony |
| Epidote Schist | Foliated | Volcanic or pelitic protoliths | Low–medium grade; epidote, chlorite, quartz |
| Graphitic Marble | Non-foliated | Carbonate with organic matter | Varied grade; calcite, graphite |
Images and Descriptions
Slate
Fine-grained, dull, fissile rock that splits into flat sheets. Forms from shale under low-grade burial and regional stress. Common roof and floor slate historically; found in Wales, Vermont, Spain. Identification: very fine foliation and smooth, flat surfaces.
Phyllite
Glossy, silky sheen and wrinkled foliation between slate and schist. Forms with slightly higher temperature than slate. Common in regional metamorphic belts; used occasionally as decorative stone. Identification: lustrous phyllitic sheen and fine foliation.
Mica Schist
Coarse, easily split rock dominated by mica, giving shiny surfaces and pronounced foliation. Forms from mudstones under medium-grade metamorphism. Occurs in mountain belts worldwide; used as building stone and landscaping. Identification: abundant visible mica flakes.
Garnet Schist
Schist with conspicuous garnet porphyroblasts in a mica-rich matrix. Forms under medium temperatures and pressures. Found in regional metamorphic terranes and used as a geologic indicator of metamorphic conditions. Identification: red to brown rounded garnet crystals.
Chlorite Schist
Greenish, flaky schist rich in chlorite giving a soft feel. Forms during low-temperature metamorphism of mafic rocks or pelites. Common in low-grade belts; identification by green color and soft, platy minerals.
Greenschist
Green, schistose rock produced under greenschist-facies metamorphism of basalts. Often found in subduction-related and regional belts. Not typically decorative but important in tectonic studies. Identification: green minerals and sheet-like foliation.
Amphibolite
Dark, dense rock dominated by amphibole and plagioclase. Forms from mafic protoliths at moderate to high temperatures; common in mountain roots. Used as crushed stone; ID by dark color and amphibole crystals.
Hornblende Schist
Foliated, dark schist with abundant hornblende giving a linear mineral alignment. Forms from mafic protoliths under regional metamorphism. Found in orogenic belts; identification by visible hornblende needles and foliation.
Gneiss
Coarse, banded rock with alternating light and dark mineral layers. Forms under high-grade regional metamorphism; common in continental shields and mountain cores. Used architecturally and as crushed stone. ID: obvious compositional banding and coarse grains.
Orthogneiss
Gneiss derived from igneous protoliths, retaining feldspar-rich bands. Common in continental crust; used decoratively and in geological mapping. Identification: gneissic banding with igneous mineralogy.
Paragneiss
Gneiss formed from sedimentary protoliths, often showing concordant layering and banding. Occurs in high-grade metamorphic terrains; identification by banded texture and sedimentary-derived mineral compositions.
Migmatite
Mixed metamorphic–igneous rock showing streaks of partial melt (leucosomes) and darker residual layers. Forms at temperatures near melting in crustal roots. Found in deep crust exposures; ID: light migmatitic veins within banded host rock.
Granulite
High-temperature, coarse-grained rock with little hydrous minerals. Forms deep in the crust during high-temperature metamorphism. Common in ancient continental shields; identification by granular texture and absence of micas.
Quartzite
Very hard, glassy rock formed by recrystallization of sandstone. Found in mountain belts and ridges; widely used as crushed stone, countertops, and decorative rock. ID: sandy protolith texture fused into a dense, interlocking quartz mass.
Marble
Crystalline rock formed from limestone or dolostone; color varies with impurities. Famous for sculpture and architecture (Carrara marble). Identification by effervescence with dilute acid and recrystallized calcite grains.
Dolomitic Marble
Marble dominated by dolomite after metamorphism of dolostone. Used similarly to calcite marble but reacts less vigorously with acid. Found in regional metamorphic belts; ID: faint acid reaction and crystalline texture.
Hornfels
Fine-grained, tough rock formed by high-temperature contact metamorphism around intrusions. Often dark, dense, and splintery. Used as aggregate; identification by hard, non-foliated texture adjacent to igneous bodies.
Skarn
Calc-silicate rock formed where magmatic fluids alter carbonate rocks, producing diverse minerals including garnet and pyroxene. Important ore hosts for tungsten, copper. ID: coarse calc-silicate mineral assemblages near plutons.
Soapstone
Soft, soapy-feeling rock rich in talc, often used for carving, countertops, and hearths. Forms by alteration of ultramafic rocks or magnesium-rich sediments. Identification: very soft (can be scratched by fingernail), greasy feel.
Steatite
Alternate name for soapstone; soft, talc-rich metamorphic rock used commercially for carving and heat-resistant objects. Identification and uses mirror soapstone.
Serpentinite
Green to dark rock formed by hydration of ultramafic rocks in the mantle or crust. Common in ophiolites and fault zones; used as decorative stone and dimension stone. ID: serpentine minerals and slickenside textures.
Eclogite
Dense, red-green rock formed at very high pressures in subduction zones. Found in exhumed subduction complexes and studied for deep-crust processes. Identification: red garnet in green clinopyroxene matrix.
Blueschist
Blue-hued rock from subduction-zone metamorphism of basalt. Rare at surface, found in accretionary prisms. Identification: blue amphibole (glaucophane) and lawsonite; indicates high-pressure, low-temperature history.
Greenschist-facies Metabasalt
Metamorphosed basalt with green minerals and low-grade foliated textures. Common in ancient volcanic terrains and greenstone belts; often used in geologic mapping. ID: green color and fine foliation from chlorite and actinolite.
Calc-silicate Rock
Varied calc-silicate assemblages from impure carbonates; commonly formed by contact metamorphism and metasomatism. Important as skarn components and mineral hosts; ID: coarse calc-silicate minerals and reaction textures.
Metaconglomerate
Metamorphosed conglomerate where pebbles are stretched, flattened, or preserved within a recrystallized matrix. Occurs in regional metamorphic terrains; identification by rounded clasts within a metamorphic matrix.
Metasiltstone
Fine-grained metamorphic rock between slate and phyllite; shows subtle foliation and slightly coarser grains than slate. Common in regional belts; ID: fine lamination and slight sheen or mica content.
Metapelite
Term for metamorphosed clay-rich sediments producing slates, schists, and gneisses. Useful to describe pelitic sequences and mineralogy; identification by typical pelitic minerals like mica and garnet.
Meta-arkose
Metamorphosed feldspar-rich sandstone retaining some feldspar and giving a coarse, granular texture. Found in orogenic belts; useful as a record of sedimentary provenance. ID: feldspar grains in a recrystallized matrix.
Quartz-mica Schist
Schist showing abundant quartz and mica giving a sparkly appearance with pronounced foliation. Forms from a range of protoliths under medium-grade conditions. Used in landscaping and recognized by shiny mica flakes.
Graphite Schist
Dark, lustrous schist with graphite imparting a metallic sheen. Forms from organic-rich sediments; used as a minor lubricant and geologic indicator. Identification: greasy feel and black, flaky sheen.
Pyroxene Hornfels
Hard, fine-grained contact-metamorphosed mafic rock with pyroxene crystals. Occurs around intrusions; used as aggregate. ID: very hard, dense rock with fine-grained pyroxene.
Calcite Marble
Classic white-to-colored marble dominated by recrystallized calcite. Widely used in sculpture and building. Forms under low to high metamorphism of limestone; identification by calcite crystals and acid reaction.
Dolostone Marble
Marble formed from dolostone often slightly harder and less reactive to acid than calcitic marble. Used in building and ornamental stone. ID: crystalline texture with weaker acid reaction.
Hornblende Gneiss
Banded gneiss rich in hornblende indicating mafic protoliths and high-temperature metamorphism. Common in continental roots and orogenic belts; identification by coarse banding and amphibole-rich layers.
Skarnified Limestone
Localized, coarse calc-silicate rock formed where magmatic fluids alter limestones. Often hosts ore minerals and distinctive mineral assemblages. ID: coarse calc-silicate minerals and proximity to intrusions.
Rocksilk (Silicified Hornfels)
Dense, silica-cemented contact rock near intrusions with smooth fracture and silica sheen. Found adjacent to plutons; identification by hard silica-rich nature and conchoidal fracture.
Hornblendite (metamorphic)
Hornblende-dominated metamorphic rock formed from mafic precursors under amphibolite to granulite facies. Coarse and dark; occurs in tectonic roots. Identification by dominant amphibole crystals.
Serpentinized Peridotite
Peridotite altered to serpentine minerals via hydration, producing green, sometimes fibrous rock. Common in ophiolite complexes and fault zones; identification by green color, slippery feel, and serpentine foliation.
Anthracite
Highest-grade coal metamorphosed to nearly pure carbon, hard and lustrous. Used as a high-energy fuel where found; identification by shiny black appearance and high carbon content.
Mylonite
Strongly deformed, fine-grained rock formed by ductile shear and recrystallization in faults. Common in deep crustal shear zones; identification by streaky foliation, stretched grains, and ultra-fine grain size.
Phyllonite
Phyllonite is a mylonite variety with a phyllitic, laminated appearance due to abundant mica. Forms in ductile shear zones; ID: silky sheen and strong foliation at small scale.
Calcite Schist
Foliated metamorphic rock with abundant calcite, often produced from calcareous sediments under regional metamorphism. Identification by foliated calcite-rich layers and moderate hardness.
Hornfelsified Shale
Shale baked into a hard, fine-grained hornfels by nearby magma. Common around plutons; used as an indicator of contact metamorphism. ID: hard, splintery, non-foliated rock close to intrusions.
Calc-silicate Hornfels
Tough, coarse-grained hornfels with calc-silicate minerals formed by high-temperature contact metamorphism of impure carbonates. Identification: calc-silicate mineralogy and proximity to igneous intrusions.
Rhyolite-derived Schist
Schist formed from altered rhyolite under regional metamorphism, often mica-rich with preserved volcanic textures. Found in metamorphosed volcanic belts; identification by volcanic clast textures and mica foliation.
Metabauxite
Metamorphosed bauxite producing altered aluminum-hydroxide minerals and iron oxides. Rare but recognized in high-weathering terranes; identification by aluminum-rich mineral assemblages.
Metachert
Dense, very hard rock produced from recrystallized siliceous sediments or chert. Common in orogenic belts; identification by high hardness and conchoidal fracture.
Epidote Schist
Greenish schist dominated by epidote formed in low-to-medium grade metamorphism of mafic or mixed sediments. Identification: green pistachio color and epidote prisms in a foliated matrix.
Graphitic Marble
Dark, streaked marble containing graphite that gives a silvery sheen. Used decoratively and as an indicator of organic-rich protoliths. Identification: crystalline carbonate with black graphite inclusions.
