Sandstone (Ferruginous)
Arenite with Iron Oxide cement (SiO2 + Fe2O3)
Category
Browse igneous or sedimentary (water worn) specimens identified by the Rock Identifier community.
Sandstone (Ferruginous)
Arenite with Iron Oxide cement (SiO2 + Fe2O3)
Granitic Pegmatite (River Rock specimen)
Granite / Pegmatite (composed of SiO2, KAlSi3O8, and NaAlSi3O8)
Chert (White Chert/Flint)
Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)
Druzy Quartz on Limestone
Silicon Dioxide (SiO2)
Gneiss (Granitic Gneiss)
Gneiss
Magnetite (Iron Ore)
Magnetite (Fe3O4)
Glauconitic Sandstone
Glauconitic Quartz-Wacke / Sandstone (Fe(II),Fe(III),Al,Mg)2-3(Si,Al)4O10(OH)2
Limestone
Calcium Carbonate (primarily CaCO3 as Calcite or Aragonite)
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with inclusions of Iron Oxide)
White Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Milky Quartz
Silicon Dioxide (SiO2)
Sandstone
Arenite (primarily Quartz, SiO2)
Conglomerate
Conglomerate (Detrital sedimentary rock)
Red Sandstone
Arenite (primarily Quartz with Hematite cement)
Fossiliferous Limestone
Carbonate Rock (CaCO3 with organic inclusions)
Yellow Chert or Jasper
Silicon Dioxide (SiO2)
Sandstone (with ripple marks)
Arenite (SiO2 primarily)
Banded Iron Formation (BIF)
Banded Iron Formation (composed primarily of Hematite [Fe2O3], Magnetite [Fe3O4], and Chert [SiO2])
Amber
Succinite (formula varies, primarily C10H16O)
Pumice (likely)
Pumice (extrusive igneous rock)
Green Common Opal
Hydrated Silica (SiO2·nH2O)
Limestone
Calcareous Sedimentary Rock (CaCO3)
Limestone (with Iron-Oxide staining)
Sedimentary Calcium Carbonate (CaCO3)
Limestone
Sedimentary Calcium Carbonate (CaCO3)
Limestone
Sedimentary Calcium Carbonate (CaCO3)
Red Sandstone
Arenite (primarily Quartz SiO2 with Hematite Fe2O3 cement)
Red Sandstone
Arenite (ferruginous sandstone)
Fossiliferous Limestone (Coral Fossil)
Scleractinian Coral in Calcium Carbonate (CaCO3)
Amber
Succinite
Pyrite
Pyrite (Iron Disulfide), FeS2
Jasper with Epidote (Unakite-related)
Epidotized Quartzite (composed of Quartz, Epidote, and Feldspar)
Quartz Vein in Host Rock (Likely Slate or Shale)
Hydrothermal Quartz (SiO2) in Pelitic host rock
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
Chalcedony (Pink/Gray variety)
Silicon Dioxide (SiO2)
Turquoise
CuAl6(PO4)4(OH)8·4H2O (Hydrated copper and aluminium phosphate)
Opal
Hydrated amorphous silica (SiO2·nH2O)
Limestone
Calcium Carbonate (CaCO3)
Chert Pebble
Chert (composed primarily of Microcrystalline Quartz, SiO2)
Rock Salt / Halite Crust
Halite (Sodium Chloride, NaCl)
Bumblebee Jasper (technically a type of Agate/Anhydrite)
Calcite and Anhydrite with inclusions of Realgar and Orpiment (As2S3)