Amethyst Geode
Amethyst (Silicon Dioxide), Formula: SiO2
mineral
Category
Sedimentary (Biogenic)
Browse sedimentary (biogenic) specimens identified by the Rock Identifier community.
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Sandstone (with Arkose characteristics)
Clastic sedimentary rock (SiO2 with KAlSi3O8)
sedimentary
Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Chert (or Flint)
Chert (SiO2)
sedimentary
River Rocks (Basalt and Sedimentary Stones)
Mafic Igneous Rock (Basalt) and Clastic Sedimentary Rock
igneous and sedimentary
Barite Rose on Marcasite
Barium Sulfate (BaSO4) on Iron Sulfide (FeS2)
mineral
Red Jasper
Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions
sedimentary
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily Quartz with Limonite/Goethite staining)
sedimentary
Banded Chert / Jasper
Silicon Dioxide (SiO2)
sedimentary
Sandstone
Arenite or Sandstone
Sedimentary Rock
Shale with Vein Infillings
Shale (a fine-grained clastic sedimentary rock). The veins could be Calcite (CaCO3), Quartz (SiO2), or other minerals.
Sedimentary Rock
Sandstone
Sandstone (clastic sedimentary rock)
sedimentary
Fossiliferous Limestone
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Sandstone
Arenite (Clastic Sedimentary Rock)
sedimentary
Travertine
Terrestrial Sedimentary Limestone (CaCO3)
sedimentary
Sandstone
Arenite (Clastic Sedimentary Rock)
sedimentary
Limestone
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Banded Chert
Chert (a microcrystalline variety of quartz, SiO2 with minor impurities)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone
Arenite (SiO2 predominantly)
sedimentary
Bivalve Fossil (Clam)
Class Bivalvia, likely Mercenaria or similar genus
fossil
Selenite (variety of Gypsum)
Calcium sulfate dihydrate (CaSO4·2H2O)
mineral
Sandstone
Sandstone (lithified arenite/wacke)
Sedimentary Rock
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Sandstone
Sandstone (clastic sedimentary rock)
sedimentary
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Fossiliferous Limestone
Limestone with fossil bioclasts (Calcium Carbonate, CaCO3)
sedimentary
Sandstone (Quartzose Sandstone)
Clastic Sedimentary Rock (composed mostly of SiO2)
sedimentary
Quartzite
Quartzite (SiO2)
metamorphic
Chert (Jasper variation)
Chert (Microcrystalline Silicon Dioxide, SiO2)
sedimentary
Shale
Shale (composition varies: primarily clay minerals and quartz)
sedimentary
Sandstone with Iron Oxide
Arenite (SiO2 with Fe2O3 staining)
sedimentary
Sandstone (River Rock)
Arenite (SiO2 principal component)
sedimentary
Sandstone
Arenite (primarily Quartz Sandstone)
sedimentary
Limestone Fragment
Sedimentary rock (primarily Calcium Carbonate, CaCO3)
sedimentary
Banded Iron Formation (BIF) / Iron Ore
Banded Iron Formation (composed primarily of Hematite (Fe2O3) and Magnetite (Fe3O4) with Quartz/Chert)
sedimentary
Sandstone
Arenite (SiO2 based)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Sandstone (Greywacke)
Sandstone (SiO2 enriched with lithic fragments)
sedimentary
Celadonite in Basalt (Green Earth)
Celadonite (K(Mg,Fe2+)(Fe3+,Al)Si4O10(OH)2)
mineral
Sandstone
Arenite
sedimentary