Rough Green Sapphire (Corundum)
Corundum (Al2O3 - Aluminum Oxide with trace elements)
mineral
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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Basalt
Basalt (Aphanitic Mafic Igneous Rock)
Igneous
Copper-bearing Quartz (with Malachite and Iron Oxides)
Quartz (SiO2) with Malachite (Cu2CO3(OH)2) and Hematite/Limonite (Fe2O3)
Mineral Specimen
Vesicular Basalt with Pyrite
Basalt (MgFe2+)(Si,Al)2O6 containing FeS2 inclusions
igneous
River Pebble (Gabbro or Basalt)
Mafic Igneous Rock (composed primarily of Pyroxene and Plagioclase Feldspar)
igneous
Smoky Quartz (Tumbled)
Smoky Quartz (SiO2 - Silicon Dioxide)
mineral
Granitic Gneiss
Gneiss (high-grade metamorphic rock primarily of quartz, feldspar, and mica)
metamorphic
Orthoclase (Potassium Feldspar)
KAlSi3O8 (Potassium Aluminum Silicate)
mineral
Dalmatian Jasper
Aplite with Arfvedsonite inclusions
igneous
Gneiss
Metamorphic Gneiss (High-grade regional metamorphism)
metamorphic
Granite
Granite (Phaneritic igneous rock composed of Quartz, Feldspar, and Mica)
igneous
Unakite
Epidotized Granite
metamorphic
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Mica Schist
Mica Schist (primarily Muscovite or Biotite sheet silicates)
metamorphic
Blue Quartzite
Quartzite with inclusions (SiO2)
metamorphic
Opalite
Man-made Glass (Synthetic Opalized Glass)
mineral
Gneiss
Gneiss
metamorphic
Ferruginous Quartz (Iron-stained Quartz)
Quartz with Iron Oxide inclusions (SiO2 with Fe2O3)
mineral
Tiger's Eye (Tumbled Blue/Black-Golden variety)
Pseudomorph of Quartz after Crocidolite (SiO2 with Iron inclusions)
metamorphic
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Mineral
Red Sandstone
Arenite (primarily SiO2 with Fe2O3)
sedimentary
Diorite
Intermediate plutonic igneous rock
igneous
Graphic Granite
Pegmatitic Granite (Quartz and Microcline K-Feldspar mixture)
igneous
Geode with Quartz and Chalcedony
Silicon Dioxide (SiO2)
sedimentary
Gastropod Fossil (Snail Internal Mold)
Gastropoda; internal mold (steinkern), often composed of Calcium Carbonate (CaCO3) or Silica (SiO2)
sedimentary
Basalt with Weathering Rind
Basalt (Mafic volcanic rock)
igneous
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Fighting Conch (Sea Shell)
Strombus alatus (primarily composed of Calcium Carbonate / CaCO3)
mineral
Blue Quartzite
Silicon Dioxide (SiO2) with inclusions
metamorphic
Sandstone (Ferruginous/Banded)
Clastic Terrigenous Sandstone (SiO2 with Fe2O3 cement)
sedimentary
Basalt with Calcite Veins
Aphanitic mafic volcanic rock with CaCO3 inclusions
igneous
Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
metamorphic
Banded Chalcedony (Agate)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Serpentinite
Serpentinite (composed mainly of Group: Serpentine; (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4)
metamorphic
Diamond Drill Core (Greenschist and Quartzite)
Chlorite Schist / Meta-quartzite (Metamorphic Rock Core Sample)
metamorphic
Gold Nugget
Native Gold (Au)
mineral
Soapstone (Steatite)
Steatite (primarily Talc: Mg3Si4O10(OH)2)
metamorphic
Pearl
Organic gemstone (Calcium carbonate - CaCO3)
mineral
Quartz Vein in Matrix
Silicon Dioxide (SiO2)
mineral
Limonite with Hematite
Hydrated iron(III) oxide-hydroxide with variable composition (FeO(OH)·nH2O)
mineral
Quartzite River Rock
Metamorphic Quartzite (primarily SiO2)
metamorphic
River Jasper (Chert/Chalcedony mix)
Silicon Dioxide (SiO2) with iron oxide and chlorite inclusions
sedimentary