Limonite/goethite-rich ironstone
Hydrated iron oxides, chiefly goethite (α-FeO(OH)) and limonite (FeO(OH)·nH₂O)
mineral
Category
Mineral (Pseudomorph)
Browse mineral (pseudomorph) specimens identified by the Rock Identifier community.
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Amethyst
Amethyst (Silicon Dioxide, SiO2)
mineral
Orthoclase Feldspar
Orthoclase (KAlSi3O8)
mineral
Granite
Granite
Igneous
Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Marble
Recrystallized Calcite (CaCO3)
metamorphic
Unidentified dark mineral/rock fragment
Indeterminate; appearance may fit a sulfide-bearing rock or iron-rich mineral
mineral
Limonite
FeO(OH)•nH2O
mineral
Tumbled quartz-rich pebble (likely quartzite or vein quartz)
Quartz (SiO₂), possibly quartzite with minor iron-oxide staining
metamorphic
Quartz Mineral
Silicon Dioxide (SiO2)
mineral
Fluorite and Mineral Collection
Calcium Fluoride (CaF2)
mineral
Ruby (Raw Corundum)
Al2O3 (Aluminum Oxide)
mineral
Iron-oxide-stained rock with a pale mineral vein
Likely limonite/goethite-stained quartz-bearing rock; exact identification is uncertain from the image
sedimentary
Sandstone
SiO2 (predominantly quartz sand)
sedimentary
Granite
Granite (composed of Quartz, Feldspar, and Mica)
igneous
Magnetite (Lodestone)
Iron(II,III) oxide (Fe3O4)
mineral
Copper Ore Specimen
Cupriferous Rock / Malachite-bearing ore
mineral
Unidentified dark metallic sulfide specimen
Possibly pyrite-, chalcopyrite-, or galena-bearing ore; exact identification requires testing
mineral
Likely weathered granite or granitic gneiss
Quartz–feldspar–mica rock; possibly gneissic granite
igneous
Carved serpentine pendant
Serpentine-group minerals, commonly antigorite/lizardite (Mg₃Si₂O₅(OH)₄), possibly mixed with chlorite or other inclusions
mineral
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Orthoclase Feldspar (Potassium Feldspar)
KAlSi3O8 (Potassium Aluminum Silicate)
mineral
Quartz–feldspar pegmatite mineral specimen
Quartz (SiO₂) with potassium feldspar, albite, mica, and likely garnet or tourmaline
igneous
Quartz in Limonite-rich Matrix
Silicon Dioxide (SiO2) with Goethite/Limonite FeO(OH)·nH2O
Mineral in Sedimentary/Secondary host
Gneiss
Gneiss (Metamorphic Rock)
metamorphic
Schist
Schist (various mineralogical compositions including mica, chlorite, talc, etc.)
Metamorphic
Banded Gneiss (Variety of Gneiss)
Gneiss (specifically, a variety exhibiting prominent banding; mineral composition can vary, but often contains quartz, feldspar, mica, and amphibole)
Metamorphic Rock
Rhodochrosite
Manganese Carbonate (MnCO3)
mineral
Magnetite
Fe3O4 (Iron(II,III) oxide)
mineral
Fluorite (Fluor-spar)
Calcium Fluoride (CaF2)
mineral
Fluorite with Quartz
Fluorite (CaF2) and Quartz (SiO2)
mineral
Polished blue copper mineral, likely chrysocolla or dyed howlite
Chrysocolla: hydrated copper phyllosilicate, approximately (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O; visual identification is uncertain from the image
mineral
Bornite
Bornite (Cu5FeS4)
mineral
Pyrite with Quartz
Iron Sulfide (FeS2) with Silicon Dioxide (SiO2)
mineral
Fossilized Gastropod / Coral
Phylum Mollusca / Cnidaria (Silicified or Calcified)
fossil
Quartz with Associated Minerals
Silicon Dioxide (SiO2)
mineral
Likely garnet crystal (rough fragment)
Garnet group; possibly almandine, Fe₃Al₂(SiO₄)₃
mineral
Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Sandstone (with Limonite staining)
Arenite (primarily SiO2 with FeO(OH)·nH2O)
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Limonite
FeO(OH)·nH2O
mineral
Pyrite
Iron Sulfide (FeS2)
mineral