Ruby (Corundum)
Al2O3 (Aluminium oxide with Chromium impurities)
Mineral
Category
Metamorphic Or Sedimentary Depending On Local Grade
Browse metamorphic or sedimentary depending on local grade specimens identified by the Rock Identifier community.
Orthoclase (Potassium Feldspar)
KAlSi3O8 (Potassium Aluminum Silicate)
mineral
Conglomerate
Conglomerate (clastic sedimentary rock type)
sedimentary
Moqui Marble (Moqui Ball)
Ironstone Concretion (Goethite/Hematite cemented Sandstone)
sedimentary
Conglomerate
Conglomerate (Rock composed predominantly of rounded clasts > 2mm)
sedimentary
Carnelian
Chalcedony (cryptocrystalline quartz), SiO2 (Silicon Dioxide)
mineral
Yellow Calcite
Calcium Carbonate (CaCO3)
mineral
Quartz Crystal Fragment
Silicon Dioxide (SiO2)
mineral
Note: Image shows a biological specimen (Rat), not a rock. Representative geological equivalent: Galena (due to lead-grey colors in fur).
Galena (PbS)
mineral
Nephrite Jade
Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)
metamorphic
Pyrite
Iron Disulfide (FeS2)
mineral
Sapphire (Corundum)
Corundum (Al2O3)
mineral
Muscovite (Mica) in Quartz Matrix
Muscovite (KAl2(AlSi3O10)(OH)2) and Quartz (SiO2)
mineral
Green Aventurine (likely)
Silicon dioxide (SiO2) with fuchsitemica inclusions
Mineral (specifically a variety of Quartz)
Green Aventurine
Quartz (SiO2) with Fuchsite inclusions
Mineral
Green Aventurine
Aventurine (a variety of Quartz, SiO2 with fuchsite inclusions)
Mineral
Limonite Sandstone
Ferruginous Sandstone (Hydrated Iron Oxide)
sedimentary
Ironstone Pebble
Ferruginous sedimentary rock (Fe2O3 / FeO(OH) mixed with SiO2)
sedimentary
Ironstone (likely siderite or goethite-rich siltstone)
Ferruginous Siltstone
sedimentary
Tanzanite
Blue Zoisite (Ca2Al3(SiO4)(Si2O7)O(OH))
mineral
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Alexandrite in Matrix
Chrysoberyl (BeAl2O4 with Chromium impurities)
mineral
Pink Sapphire
Corundum (Al2O3 with Chromium/Titanium/Iron traces)
mineral
Conglomerate
Conglomerative Sedimentary Rock
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Pyrite (on the right) and Magnetite or Hematite (on the left)
Iron Sulfide (FeS2) and Iron Oxide (Fe3O4 or Fe2O3)
mineral
Ferruginous Sandstone
Sandstone (arenite) with Limonite/Goethite cement
sedimentary
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Tiger's Eye (Golden)
Pseudomorph of Quartz after Crocidolite (SiO2 with FeOOH inclusions)
mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Ferruginous Sandstone (Ironstone)
Sedimentary rock with Limonite/Goethite cement
sedimentary
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Banded Iron Formation (Jasper-Hematite)
Banded Iron Formation (BIF); composition primarily Hematite (Fe2O3) and Chalcedony/Quartz (SiO2)
sedimentary
Fossilized Megalodon Tooth Fragment
Otodus megalodon (Carcharocles megalodon fossil)
sedimentary
Blue Sapphire
Corundum (Al2O3) with traces of Iron and Titanium
mineral
Coal (likely Anthracite)
Anthracite coal
sedimentary
Marble
Recrystallized Carbonate Rock (CaCO3)
metamorphic
Limonite (Ironstone)
Limonite (FeO(OH)·nH2O)
mineral
Sandstone (likely Quartzose Sandstone)
Arenite (composed primarily of SiO2)
sedimentary
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
metamorphic
Coquina / Shelly Limestone
Coquina (Biogenic Limestone)
sedimentary