Metamorphic Rock (Primarily Composed Of Minerals)

Browse metamorphic rock (primarily composed of minerals) specimens identified by the Rock Identifier community.

Yellow Quartzite (River Pebble)

Quartzite (primarily Silicon Dioxide, SiO2)

metamorphic

Serpentine

Serpentine-group ((Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al,Fe)2O5(OH)4)

metamorphic

Hematite

Iron(III) oxide (Fe2O3)

mineral

Sandstone

Clastic Sedimentary Rock (composed mostly of quartz, SiO2)

sedimentary

Sandstone

Clastic Sedimentary Rock (composed of SiO2 grains)

sedimentary

Quartz with Iron Stains

Quartz (SiO2) with iron oxide/hydroxide staining

Mineral

Black Marble

Recrystallized Carbonate Rock (CaCO3)

metamorphic

Epidote (Unakite-related)

Epidote (Ca2(Al,Fe)3(SiO4)3(OH))

metamorphic

Aventurine

Aventurine Quartz (SiO2 with inclusions)

Mineral

Garnet

Garnet Group (Silicate mineral); general formula X3Y2(SiO4)3

Mineral

Banded Gneiss

Gneiss (typically quartz, feldspar, mica, amphibole composition)

metamorphic

Orthoclase Feldspar

Orthoclase (KAlSi3O8)

mineral

Red Garnet

Almandine and Pyrope (Silicate minerals: Fe3Al2(SiO4)3 and Mg3Al2(SiO4)3)

mineral

Shale

Shale (clastic sedimentary rock)

Sedimentary

Biotite Mica

K(Mg,Fe)3AlSi3O10(OH)2

Mineral in a matrix (likely quartz or feldspar)

Blue Quartzite

Quartzite (silicon dioxide, SiO2)

metamorphic

Sandstone (likely Arkosic)

Clastic Sedimentary Rock (primarily SiO2 with Feldspar)

sedimentary

Dragon Blood Jasper (Epidote with Piedmontite or Quartz)

Epidote-rich Quartzite / SiO2 with (Ca2(Al2,Fe)(Si2O7)(SiO4)O(OH))

metamorphic

Granite

Granite (composed of Quartz, Alkali Feldspar, and Plagioclase)

igneous

Quartzite with Hematite

Metamorphosed Quartz Sandstone (SiO2 with Fe2O3 inclusions)

metamorphic

Diorite

Diorite (Intermediate intrusive igneous rock)

igneous

Clear Quartz

Silicon Dioxide (SiO2)

mineral

Septarian Nodule

Septarian Concretion (CaCO3 with Siderite/Limonite streaks)

sedimentary

Unakite

Epidotized Granite

metamorphic

Chalcedony or Chert/Jasper with secondary mineral staining

SiO2 (for chalcedony/quartz) with possible secondary copper minerals (e.g., CuSiO3·nH2O for chrysocolla, Cu2(CO3)(OH)2 for malachite) or iron oxides/hydroxides.

Mineral, potentially a rock with chalcedony/jasper.

Tiger's Eye

Pseudomorph of quartz after crocidolite (SiO2 with iron oxide inclusions)

metamorphic

Orange Quartzite (River Pebble)

Quartzite (SiO2 with iron oxide inclusions)

metamorphic

Limestone with Quartz or Calcite Veining

Calcium Carbonate (CaCO3) matrix with SiO2 or CaCO3 inclusions

sedimentary

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

mineral

Greenstone (Metabaltic/Greenschist)

Chlorite schist / Meta-basalt

metamorphic

Dragon Stone (Dragon Blood Jasper)

Epidote with Pietersite or Red Jasper inclusions (varied SiO2 and Ca2(Al,Fe)3(SiO4)3(OH))

metamorphic

Quartz / Calcite Vein Rock

Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3)

mineral

Coquina

Biogenic Limestone (Calcium Carbonate - CaCO3)

sedimentary

Snowflake Obsidian

Volcanic glass with Spherulite inclusions (SiO2)

igneous

Garnet (likely Pyrope or Almandine)

Garnet Group (complex nesosilicate minerals, e.g., Pyrope Mg3Al2(SiO4)3, Almandine Fe3Al2(SiO4)3, Spessartine Mn3Al2(SiO4)3, Grossular Ca3Al2(SiO4)3, Andradite Ca3Fe2(SiO4)3, Uvarovite Ca3Cr2(SiO4)3). The vivid red color in the image strongly suggests Pyrope or Almandine.

Mineral