Blue Sapphire
Corundum (Al2O3)
mineral
Category
Sedimentary Or Metamorphic (Base Substrate)
Browse sedimentary or metamorphic (base substrate) specimens identified by the Rock Identifier community.
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Dendritic Agate (or Dendritic Opal)
SiO2 (for Agate), SiO2·nH2O (for Opal)
Mineral
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Citrine Quartz
Citrine (Silicon Dioxide, SiO2)
mineral
Orca Agate
Chalcedony (Microcrystalline Quartz, SiO2)
sedimentary
Schist
Mica Schist
metamorphic
Greenschist (Chlorite Schist)
Greenschist (Metamorphic rock dominated by chlorite, actinolite, and epidote)
metamorphic
Red Sandstone
Arenite (SiO2 based with Fe2O3)
sedimentary
Milky Quartz with Mica (Gneiss/Schist influence)
Silicon Dioxide (SiO2) with Phyllosilicates
igneous/metamorphic
Limestone (likely weathered)
Limestone (Mainly Calcium Carbonate, CaCO3)
sedimentary
Crushed Stone Ballast
Crushed Limestone or Granite Aggregate
sedimentary
Sandstone (Calcareous/Lithic)
Sedimentary Rock (Clastic Sandstone with Calcium Carbonate cement)
sedimentary
Limestone
Sedimentary rock composed primarily of Calcium Carbonate (CaCO3)
sedimentary
Coquina
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
River Stone (Greywacke)
Greywacke (immature sandstone)
sedimentary
Coquina or Fossiliferous Limestone
Fossiliferous Limstone (CaCO3)
sedimentary
Sandstone
Arenite (primary component SiO2)
sedimentary
Graywacke
Lithic Sandstone (Graywacke)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Chert (or Flint)
Chert (SiO2)
sedimentary
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Desert Varnish on Sandstone
Ferromanganese coating on Quartz Arenite
sedimentary
Mixed Gemstone Bracelet
Mixed natural minerals and rocks (e.g., Rhodonite, Malachite, Sodalite, Rose Quartz, Black Tourmaline, Quartz/Chalcedony variants)
Mineral/Rock assemblage
Quartzite
Quartzite (Mostly SiO2)
metamorphic
Quartzwacke / Impure Sandstone
Arenite with minor lithic fragments (Silicon Dioxide matrix)
sedimentary
River Rock (Quartzite/Chert conglomerate)
Quartzite (SiO2)
metamorphic
Pebble
Lithic fragment (Quartzite or general rock pebble)
sedimentary
Sandstone (Greywacke)
Arenite / Greywacke Sandstone
sedimentary
Chert with Quartz Veining
Microcrystalline silica (SiO2)
sedimentary
Quartz Vein in Host Rock
Silicon Dioxide (SiO2)
mineral
Sandstone with Manganese Dendrites
Clastic Sedimentary Rock (SiO2 based with MnO2 inclusions)
sedimentary
Graywacke
Lithic Sandstone (Graywacke)
sedimentary
Crushed Stone / Gravel
Aggregatus saxum (variable mineral composition)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Coquina (Fossiliferous Limestone)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Garnet Schist
Almandine Garnet Schist (Fe3Al2(SiO4)3 in Schistose matrix)
metamorphic
Carnelian
Carnelian (a variety of Chalcedony, SiO ₂)
Mineral (specifically a variety of Chalcedony, which is a cryptocrystalline quartz)
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
K2 Jasper (K2 Granite)
Azurite in Granite (Biotite Granite containing Azurite)
igneous
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Limestone with Iron Inclusions
Calcium Carbonate (CaCO3) with Hematite/Limonite
sedimentary