Anthracite Coal with Sulfur staining
Anthracite (Carbon C with impurities)
metamorphic
Category
Metamorphic Rock (Primarily Composed Of Minerals)
Browse metamorphic rock (primarily composed of minerals) specimens identified by the Rock Identifier community.
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Sandstone (Quartzose)
Arenite (primarily SiO2)
sedimentary
Granite
Phaneritic plutonic igneous rock (mostly SiO2 and Al2O3)
igneous
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Diorite
Phaneritic plutonic rock (dominated by plagioclase feldspar and hornblende)
igneous
Quartzite
Quartzite (primarily SiO2)
metamorphic
Quartzite
Quartzite (primarily SiO2)
metamorphic
Turquoise
CuAl6(PO4)4(OH)8·4H2O
mineral
Ferruginous Sandstone (Red Sandstone)
Arenite with Hematite/Limonite cement
sedimentary
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
sedimentary
River Cobble (Diorite or Meta-volcanic with Quartz Veining)
Diorite (with SiO2 quartz veins)
igneous
Limonite Concretion
Limonite (Hydrated iron(III) oxide-hydroxides, FeO(OH)·nH2O)
sedimentary
Green Opal
Hydrated Silica (SiO2·nH2O)
mineraloid
Quartz
Quartz (SiO₂ - Silicon Dioxide)
Mineral
Clear Quartz (or Rock Crystal)
Quartz (SiO₂)
Mineral
Ironstone Concretion (Moqui Marble)
Iron Oxide Concretion (Fe2O3 / FeO(OH) mixed with SiO2)
sedimentary
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Travertine (Calcareous Tufa)
Calcium Carbonate (CaCO3)
sedimentary
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock)
igneous
Quartzite
Quartzite (primarily SiO2)
metamorphic
Magnetite with Quartz
Magnetite (Fe3O4)
mineral
Granite
Granite (High-silica plutonic rock)
igneous
Fossiliferous Siltstone
Clastic Sedimentary Rock with Fossil Inclusions
sedimentary
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
sedimentary
Orange Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Druzy Quartz
Crystalline Silicon Dioxide (SiO2)
mineral
Blue Quartz with Dumortierite/Magnesio-riebeckite inclusions
Quartz (SiO2) containing Dumortierite (Al7(BO3)(SiO4)3O3)
igneous/metamorphic
Jade (likely Nephrite Jade based on appearance)
Nephrite (a variety of actinolite, Ca2(Mg,Fe)5Si8O22(OH)2)
Mineral
Shale with Iron Oxide Staining
Fissile Mudstone (primarily clay minerals and quartz)
sedimentary
Serpentine
Serpentine Group Minerals (e.g., Antigorite, Chrysotile, Lizardite)
Mineral, often found as a rock
Rhodonite in Quartz Matrix
Rhodonite (Manganese Silicate - (Mn,Fe,Mg,Ca)SiO3)
mineral
Moqui Marble (Shaman Stone)
Iron Oxide Concretion (Goethite/Hematite shell with Sandstone core)
sedimentary
Jadeite Jade
NaAlSi2O6 (Sodium Aluminum Silicate)
metamorphic
Turquoise
Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)
mineral
Tiger's Eye (likely Hawk's Eye variant)
Pseudomorph of Quartz after Crocidolite (SiO2)
metamorphic
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with inclusions of Iron Oxide)
metamorphic
Fossilized Coral
Scleractinia (fossil order), primarily Calcium Carbonate (CaCO3)
sedimentary
Diorite
Diorite (Intermediate Plutonic Rock)
igneous
Quartz
Quartz (SiO2 - Silicon Dioxide)
Mineral
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, formula: SiO2)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) in Geode form
sedimentary
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock)
igneous