Brachiopod Fossil in Matrix
Phylum Brachiopoda
fossil
Category
Mineral, Possibly Rock Fragment Containing A Mineral
Browse mineral, possibly rock fragment containing a mineral specimens identified by the Rock Identifier community.
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Granite
Intrusive igneous rock
igneous
Granitic Gneiss
Gneiss (containing Potassium Feldspar and Quartz)
metamorphic
Basalt with Olivine (Peridot)
Basalt containing (Mg,Fe)2SiO4
igneous
Shale fragment
Shale (clay mineral rich sedimentary rock)
sedimentary
Basalt with Amygdules
Extrusive Igneous Rock (Mafic)
igneous
Sandstone (with potential Arkose/Lithic characteristics)
Arenite (Sedimentary rock composed of sand-sized grains)
sedimentary
Tooth or shell fragment (likely fossilized marine material)
Indeterminate; possibly a fossil fish tooth or mollusk shell fragment composed mainly of calcium carbonate (CaCO₃)
fossil
Sandstone
Arenite
sedimentary
Sandstone (with carbonaceous plant fragments)
Arenite (composed primarily of SiO2)
sedimentary
Iron meteorite fragment (likely meteorite slice)
Fe–Ni metallic meteorite, possibly an octahedrite; exact classification requires laboratory analysis
meteorite
Granite
Intrusive Igneous Rock
igneous
Quartz with Mica
Silicon Dioxide (SiO2) with Mica group inclusions
mineral
Hag Stone
Perforated sedimentary rock (typically sandstone or limestone)
sedimentary
Dark flint or chert fragment
Microcrystalline quartz (SiO₂), likely flint/chert
sedimentary
Chert (Arrowhead Fragment)
Chert / Microcrystalline Silicon Dioxide (SiO2)
sedimentary
Lapis Lazuli
Lazurite-dominant Metamorphic Rock (complex aluminosilicate)
metamorphic
Sandstone (Ferruginous)
Ferruginous Sandstone (SiO2 with Fe2O3)
sedimentary
Granodiorite
Granodiorite (containing Quartz, Plagioclase Feldspar, Biotite, and Hornblende)
igneous
Veined Pebble (likely a Quartz-Veined Pebble)
Pebble with Mineral Vein (e.g., Quartz Vein in a Chert/Mudstone Pebble)
Sedimentary Rock (possibly conglomerate or breccia with a quartz vein)
Galena-bearing sulfide ore
Galena (lead sulfide, PbS), possibly mixed with pyrite or other sulfides
mineral
Sandstone (Quartzose)
Arenite (primarily SiO2)
sedimentary
Smooth river pebble
Indeterminate lithology; likely fine-grained quartz-rich sandstone, siltstone, or weathered chert
sedimentary
Weathered limestone or calcareous sandstone
Calcite-rich carbonate rock, chiefly calcium carbonate (CaCO₃), possibly fossiliferous limestone
sedimentary
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock)
igneous
Limonite with Opal infusion
FeO(OH)·nH2O (Limonite) / SiO2·nH2O (Opal)
mineral
Basalt with Phenocrysts
Extrusive Igneous Rock
igneous
Sandstone
Arenite (SiO2 based)
sedimentary
Sandstone (Ferruginous)
Arenite (Fe-rich SiO2)
sedimentary
Sandstone Pebble
Arenite (primarily SiO2)
sedimentary
Glauconitic Sandstone with possible Trace Fossil
Glauconitic Sandstone (K(Fe,Al)2(Si,Al)4O10(OH)2)
sedimentary
Mixed rock and mineral collection
Mixed lithologies; likely quartz, feldspar, basalt, granite, chert, sandstone, and metamorphic rocks
igneous, sedimentary, metamorphic, mineral
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Sandstone (River Pebble)
Clastic Sedimentary Rock (primarily Quartzite/Arenite)
sedimentary
Sandstone (Stream-rounded Cobble)
Arenite (composed primarily of SiO2, Silica)
sedimentary
Polished brecciated jasper (likely septarian or iron-rich jasper)
Microcrystalline quartz (chalcedony), SiO₂, with iron oxides and possibly calcite or other rock fragments
sedimentary
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Rhyolite with Lithophysae and Iron Oxide
Extrusive igneous rock / Felsic volcanic rock
igneous
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Porphyritic Basalt
Porphyritic Basalt (with Plagioclase and Augite phenocrysts)
igneous
Vesicular Basalt
Vesicular Basalt
igneous
Gabbro
Basaltic Plutonic Rock (Gabbro)
igneous