Red Sandstone (Old Red Sandstone)
Ferruginous Sandstone (SiO2 + Fe2O3)
sedimentary
Category
Not A Rock (Man Made Polymer)
Browse not a rock (man made polymer) specimens identified by the Rock Identifier community.
Sandstone (Quartzite-rich River Cobble)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone (likely with Quartz Veining)
Arenite (primarily SiO2)
sedimentary
Fossilized Coral
Scleractinia (fossil order), primarily Calcium Carbonate (CaCO3)
sedimentary
Granodiorite
Granodiorite (calc-alkaline phaneritic igneous rock)
igneous
Basalt Arrowhead (worked stone)
Aphanitic mafic volcanic rock (Basalt)
igneous
Quartz with Mica Schist (Pegmatite Specimen)
SiO2 (Silicon Dioxide) and Phyllosilicates (Biotite/Muscovite)
Igneous/Metamorphic Hybrid
Geode (Chert or Quartz Nodule)
Silicon Dioxide (SiO2)
sedimentary
Druzy Quartz (on Chalcedony/Agate base)
Silicon Dioxide (SiO2)
mineral
Pumice
Pumice (Vesicular volcanic glass / Rhyolite or Trachyte)
igneous
Schist
Mica Schist
metamorphic
Chert (Nodule)
Silicon dioxide (SiO2) - Cryptocrystalline Quartz
sedimentary
Quartzite
Quartzite (primarily SiO2)
metamorphic
Amethyst
Amethyst (Silicon Dioxide, SiO2)
mineral
Quartzite
Quartzite (primarily SiO₂)
metamorphic
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide)
mineral
Chert (Jasper/Flint variation)
Chert (SiO2)
sedimentary
Amethyst on Agate/Basalt Matrix
Silicon Dioxide (SiO2) with iron impurities
mineral
Sandstone (Greywacke/Siltstone variant)
Clastic Sedimentary Rock (Lithic Wacke)
sedimentary
Quartzite (River Pebble)
Metamorphosed Quartz Sandstone (SiO2)
metamorphic
Quartz Pebble
Quartz (Silicon Dioxide - SiO2)
mineral
Crinoid Fossil in Limestone
Class Crinoidea in Carbonate Matrix (CaCO3)
sedimentary
Emerald with Matrix (Emerald in Mica Schist)
Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities
mineral
Hag Stone
Siltstone or Fine-grained Sandstone with boring (e.g., Lithophaga impact)
sedimentary
Chert (White Chert/Flint)
Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)
sedimentary
Limonite (Iron Ore)
Limonite; FeO(OH)·nH2O
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Amygdaloidal Basalt
Amygdaloidal Basalt with Secondary Infilling (e.g., Agate, Quartz, or Zeolite)
igneous
Turquoise
Hydrated phosphate of copper and aluminium, CuAl6(PO4)4(OH)8·4H2O
mineral
Calcite (Yellow/Orange variety - sometimes called Honey Calcite)
Calcite
Mineral
Chert (Iron-stained)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Quartz Vein with Iron Staining
Silicon Dioxide (SiO2) with limonite/hematite staining
mineral
Green Moonstone (Garnierite)
Nickel-bearing Magnesium Silicate (often a mix of Serpentine and Talc/Chlorite groups)
mineral
Diamond
Diamond (Pure Carbon, C)
mineral
Almandine Garnet
Almandine (Fe3Al2Si3O12)
mineral
Copper Ore with Chrysocolla and Azurite
Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O (Chrysocolla) / Cu3(CO3)2(OH)2 (Azurite)
mineral
Septarian Nodule
Septarian Nodule (Mixture of Calcite, Aragonite, and Limestone/Clay)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Sandstone (Quartzose Sandstone)
Arenite (SiO2)
sedimentary
Chert (White-Tan variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Agate
Silicon dioxide (SiO2)
mineral