Limonite / Iron Oxide Concretion
FeO(OH)·nH2O (Hydrated iron oxide)
mineral
Category
Sedimentary Or Metamorphic (Low Grade)
Browse sedimentary or metamorphic (low grade) specimens identified by the Rock Identifier community.
Learn about Sedimentary Or Metamorphic (Low Grade) in the encyclopedia
View all →
Green Opal
Hydrated amorphous silica (SiO2·nH2O)
mineraloid
Heliotrope (Bloodstone)
Silicon Dioxide with Iron Oxide (SiO2)
sedimentary
Chalcedony
Cryptocrystalline Quartz (SiO2)
mineral
Yellow Chalcedony
Silicon Dioxide (SiO2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Chalcedony (Agate/Chert)
Chalcedony (Silicon Dioxide, SiO2)
mineral
Green Chalcedony
Silicon Dioxide (SiO2) with trace minerals
mineral
Chalcedony (Agate/Carnelian variant)
Silicon Dioxide (SiO2)
mineral
Blue Chalcedony
Silicon Dioxide (SiO2) - Microcrystalline Quartz
mineral
Emerald In Matrix
Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)
gemstone
Moonstone (Grey)
Feldspar (variety Orthoclase/Adularia) with the formula (K,Na)AlSi3O8
mineral
Granite or Granitic Gneiss Pebble
Granite (felsic intrusive igneous rock) or Gneiss
Igneous or Metamorphic
Serpentinite
Serpentinite (composed primarily of Serpentine group minerals like Antigorite, Lizardite, and Chrysotile)
metamorphic
Almandine Garnet
Fe3Al2(SiO4)3
mineral
Sapphire
Corundum (Al2O3)
gemstone
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Amber
Fossilized Tree Resin
gemstone
Quartzite Pebble
Quartzite (composed primarily of SiO2)
metamorphic
Bloodstone (Heliotrope)
Silicon Dioxide (SiO2) - Variety of Chalcedony/Jasper
mineral
Quartz (Clear Quartz/Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Fossil Shell Fragment (possibly Brachiopod or Bivalve)
Calcium Carbonate (CaCO3) - Phylum Brachiopoda or Mollusca
sedimentary
Magnetite-rich iron ore (probable magnetite schist)
Magnetite (Fe₃O₄) in a foliated metamorphic matrix, possibly magnetite–biotite schist
metamorphic
Anthracite Coal
Anthracite (Carbon C)
metamorphic
Garnet Schist
Almandine Garnet in Mica Schist (Fe3Al2(SiO4)3)
metamorphic
Quartzite with Iron Mineral Banding
Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3) staining
metamorphic
Epidote with Feldspar/Quartz (Unakite-like)
Epidotized Granite (Ca2(Al,Fe)3(SiO4)3(OH) + KAlSi3O8)
metamorphic
Serpentinite
Serpentinite (containing minerals of the Serpentine subgroup: Antigorite, Lizardite, and Chrysotile; formula (Mg,Fe)3Si2O5(OH)4)
metamorphic
Serpentinite
Serpentinite (containing Antigorite, Lizardite, and/or Chrysotile)
metamorphic
Serpentine (Serpentinite)
Antigorite, Lizardite, and Chrysotile: (Mg,Fe)3Si2O5(OH)4
metamorphic
Serpentinite
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4
metamorphic
Epidote
Epidote (Ca2(Al,Fe)3(SiO4)3(OH))
metamorphic
Seashell (Cockle Shell)
Cardiidae (Bivalvia), primary composition: Calcium Carbonate (CaCO3) in the form of aragonite or calcite
fossil
Rough Diamond
Diamond (pure Carbon, C)
mineral
Ruby (varietal of Corundum)
Corundum (Al2O3:Cr)
gemstone
Emerald in Matrix (Quartz/Schist)
Beryl (Be₃Al₂Si₆O₁₈) with Chromium/Vanadium impurities
mineral
Pyrite and Calcite (or Barite) Specimen
Iron Sulfide (FeS2) with Calcium Carbonate (CaCO3)
mineral
Carnelian
Silicon Dioxide (Chalcedony variety), SiO2
gemstone
Pyrite
Iron Sulfide (FeS2)
mineral
Blue Chalcedony
Silicon Dioxide (SiO2)
mineral
Chalcedony Pebble
Silicon Dioxide (SiO2)
mineral
Tumbled Onyx / Black Chalcedony
Silicon Dioxide (SiO2)
mineral