Limestone
Calcium Carbonate (CaCO3)
Category
Browse man made material specimens identified by the Rock Identifier community.
Limestone
Calcium Carbonate (CaCO3)
Limestone
Calcium Carbonate (CaCO3)
Granodiorite (River Pebble)
Granodiorite
Land Snail Shell
Gastropoda (Calcium Carbonate, CaCO3)
Limestone
Sedimentary Calcium Carbonate (CaCO3)
Granite Pebble
Granite (composed primarily of Quartz, Feldspar, and Mica)
Tumbled brown jasper
Microcrystalline quartz/chalcedony (SiO₂), commonly iron-oxide stained
Milky quartz with iron-oxide staining
Quartz (SiO₂), likely ferruginous milky quartz
Likely petrified wood or silicified fossil fragment
Silicified wood; predominantly microcrystalline quartz (SiO₂)
Chert (Nodule)
Cryptocrystalline Quartz (SiO2)
Blue quartzite or blue aventurine glass-like aggregate
Quartzite, predominantly SiO₂ (identification uncertain from image)
Quartzite
Metamorphic Quartz Sandstone
Quartzite
Metamorphic Quartzite (SiO2)
Mica schist (possibly garnet–mica schist)
Muscovite–biotite schist; chiefly quartz, feldspar, muscovite, and biotite
Black Jasper (Etched)
Silicon Dioxide (SiO2) with impurities
Red Sandstone
Arenite (Ferruginous Sandstone)
Vesicular volcanic rock, likely weathered pumice or scoria
Pumice/scoria; predominantly volcanic glass and feldspar, with possible iron oxides
Weathered quartz-rich cobble, possibly quartzite or feldspar-rich granite
Quartz–feldspar aggregate; identification is uncertain from the photograph
Limestone (River Pebble)
Calcite (Calcium Carbonate) - CaCO3
Tumbled agate (probable moss or dendritic agate)
Microcrystalline quartz, SiO₂, with iron/manganese dendritic inclusions
Weathered quartz-rich rock, possibly sandstone or quartzite
Likely quartzite (mostly SiO₂), though a granular sandstone is also possible
Rhodonite
Rhodonite (MnSiO3)
Chert (Chalk-associated Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Sandstone
Arenite
Chert (Flint Nodules)
Chert (Silicon Dioxide, SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Mica-rich schist
Muscovite–biotite schist, commonly quartz-bearing
Obsidian (Black)
Obsidian (High-silica volcanic glass)
Weathered, iron-stained rhyolite pebble (possibly rhyolitic volcanic breccia)
Rhyolite, a felsic volcanic rock; mainly quartz and alkali feldspar with minor plagioclase, altered mafic minerals, and iron-oxide staining
Quartzite
Metamorphic Rock (Mainly SiO2)
Black Jasper
Silicon Dioxide (SiO2) with impurities
Tumbled red jasper
Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored mainly by iron oxides
Red jasper (tumbled)
Jasper, microcrystalline quartz/chalcedony (SiO₂) colored mainly by iron oxides
Diabase (Greenstone)
Diabase (Dolerite)
Amber with dark mineral/organic inclusions
Fossilized plant resin (amber; chiefly polymerized diterpenoid resin)
Granite
Phaneritic Felsic Igneous Rock
Red Sandstone
Arenite (Ferruginous Sandstone)
Granite
Granite
Polished dendritic agate or jasper
Microcrystalline quartz (SiO₂), likely chalcedony with manganese-oxide dendrites
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
Hag Stone
Perforated Sedimentary Rock (typically Limestone or Sandstone)
Emerald (Rough)
Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)