Limestone (Concretionary or Tufa)
Calcium Carbonate (CaCO3)
Category
Browse igneous or sedimentary (water worn) specimens identified by the Rock Identifier community.
Limestone (Concretionary or Tufa)
Calcium Carbonate (CaCO3)
Milky Quartz with Iron Inclusions
Silicon Dioxide (SiO2)
Sandstone (Ferruginous)
Arenite (Fe-rich)
Pumice
Pumice (Vesicular Rhyolite/Andesite)
Pumice
Pumice (a volcanic glass, primarily SiO2 with Al2O3)
Scoria
Scoriaceous Basalt
Lava Rock (Scoria)
Scoria (Mafic volcanic rock)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Dalmatian Stone (often misnamed Dalmatian Jasper)
Aplite (with hornblende/arfvedsonite inclusions)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Sandstone Cobble
Clastic Sedimentary (Sandstone)
Sandstone (Weathered Pebble)
Arenite (composed primarily of SiO2)
Quartz-veined Sedimentary Rock
Hydrothermally veined Clastic Sedimentary Rock (SiO2 veins in Matrix)
Basalt River Stone
Basalt (Aphanitic Mafic Igneous Rock)
Precious Opal
Hydrated Silica (SiO2·nH2O)
Banded Gneiss
Gneiss (variable mineral composition)
Scoria (Lava Rock)
Scoria (Basaltic Scoria)
Granite Pebble
Phaneritic plutonic rock (SiO2 primary)
Granite Pegmatite with Muscovite Mica
Granite Pegmatite (Silicon Dioxide and complex silicates)
Basalt River Stone
Basalt
Granite Pebble
Felsic Plutonic Rock (primarily Quartz, Feldspar, and Mica)
Black Onyx
Silicon Dioxide (SiO2) with parallel banding
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Amazonite
Potassium Feldspar (Microcline), K(AlSi3O8)
Pumice
Pumice (a highly vesicular, silicic volcanic rock)
Banded Chert (River Pebble)
Microcrystalline Quartz (SiO2)
Sandstone (Quartzose Sandstone)
Clastic sedimentary rock (primarily SiO2)
Hag Stone
Perforated Flint or Chert (SiO2)
Chert Nodules (with Gryphaea or Shell inclusions)
Microcrystalline Quartz (SiO2) with Calcitic inclusions
Sandstone (Iron-stained)
Arenite (composed primarily of SiO2 with Fe2O3 staining)
Sandstone
Arenite (composed primarily of SiO2)
Scoria
Vesicular Basaltic Glass (comprised primarily of volcanic glass/silica with plagioclase, pyroxene, and olivine crystals)
Pumice
Pumicite
Scoria
Vesicular Basalt / Scoria (Mafic volcanic rock)
Scoria (Lava Rock)
Scoria
Limonite (Iron Ore/Hydrated Iron Oxide)
Limonite (mixture of FeO(OH)·nH₂O minerals, mainly Goethite, FeO(OH) and Lepidocrocite, FeO(OH))
Rough Quartz (Alluvial Pebbles)
Silicon Dioxide (SiO2)
Sandstone (with Iron Staining)
Clastic sedimentary rock (High Silica / Iron Oxide)
Dalmatian Stone (Dalmatian Jasper)
Dalmatian Stone (A variety of Perthite / Aplite)
Sandstone (with Concretion)
Arenite / Quartzose Sandstone
Black Limestone with Calcite Veining
Bituminous Limestone (CaCO3 with Organic Carbon inclusions)