Belemnoit Fossil (Thunderstick)
Belemnitida (Internal rostrum)
fossil
Category
Mixed (Predominantly Sedimentary And Igneous)
Browse mixed (predominantly sedimentary and igneous) specimens identified by the Rock Identifier community.
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Sandstone with Lichen and Iron Oxide Staining
Quartz Arenite / Sandstone
sedimentary
Amethyst
Silicon Dioxide with iron impurities (SiO2)
mineral
Amethyst
Amethyst (Silicon Dioxide, SiO2)
mineral
Peach Moonstone
Potassium Aluminum Silicate, KAlSi3O8
mineral
Inukshuk Rock Sculpture (composed of Granite, Slate, and Amethyst)
Silicon Dioxide (Amethyst portion, SiO2) with mixed silicate rock assemblage
mineral
Granite Boulder
Phaneritic Felsic Igneous Rock
igneous
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary
Obsidian and Phantom Quartz
Volcanic Glass (SiO2 + MgO + Fe3O4) and Crystalline Quartz (SiO2)
igneous and mineral
Weathered limestone fragment
Limestone, predominantly calcite (CaCO₃)
sedimentary
Sandstone
Sedimentary Rock (Quartz Sandstone)
sedimentary
Weathered limestone
Limestone, predominantly calcite (CaCO₃)
sedimentary
Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Ferruginous Sandstone (with Laterite)
Ferruginous Arenite (FeO(OH)·nH2O)
sedimentary
Sandstone with Quartz Crystal Infill
Quartz-cemented quartz arenite
sedimentary
Citrine
Silicon Dioxide (SiO2) with iron impurities
Mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Variscite (or potentially a turquoise/variscite matrix cabochon, or an impression jasper)
AlPO4·2H2O (Variscite) or related phosphate/silicate material depending on exact composition
Mineral
Blue Lace Agate
Silicon Dioxide (SiO2)
mineral
Amazonite
Microcline (KAlSi3O8)
mineral
Chrysocolla in Quartz
Chrysocolla (Cu,Al)2H2Si2O5(OH)4·nH2O in Quartz (SiO2)
gemstone
Graphic Granite (or Rapakivi-textured Granite)
Alkali feldspar granite
igneous
Rose Quartz Sphere
Silicon Dioxide (SiO2)
mineral
Likely pyrite-bearing rock or pyrite fragment
Pyrite (FeS₂), possibly mixed with quartz or carbonate matrix
mineral
Porphyritic Igneous Rock / Porphyry
Porphyry (Plagioclase/Quartz phenocrysts in a finer-grained groundmass)
igneous
Sandstone
Sandstone (Siliciclastic Sedimentary Rock)
sedimentary
Citrine Geode Fragment
Citrine (Silicon Dioxide with Iron Impurities), SiO2
mineral
Banded Sandstone / Quartzite with Mineral Veins
Sedimentary rock (Quartz arenite with iron oxide/silica banding)
sedimentary
Chakra Stone Bracelet
Mixed Mineral Assembly (Scoria, Amethyst, Lapis Lazuli, Turquoise/Howlite, Impression Jasper, Tiger's Eye, Carnelian, Red Jasper)
igneous, metamorphic, and sedimentary
Sandstone (Banded)
Sedimentary Clastic Rock
sedimentary
Scoria
Extrusive Mafic Volcanic Rock
igneous
Sandstone
Clastic sedimentary rock (Quartz arenite)
sedimentary
Sandstone
SiO2 (predominantly quartz sand)
sedimentary
Black Tourmaline (Schorl)
NaFe3Al6(BO3)3Si6O18(OH)4
Mineral
Citrine
Silicon Dioxide (SiO2) with iron impurities
mineral
Chrysocolla
Chrysocolla (Cu2–xAlx(H2–xSi2O5)(OH)4·nH2O)
mineral
Banded Gneiss
Gneiss (Metamorphic high-grade, predominantly SiO2, Al2O3, K2O, Na2O)
metamorphic
Tiger's Eye
Silicon dioxide (SiO2) - Pseudomorph after crocidolite
mineral
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
igneous