Chert (Chalcedony/Flint)
Microcrystalline Quartz (SiO2)
Category
Browse anthropogenic (man made material mimicking sedimentary rock) specimens identified by the Rock Identifier community.
Chert (Chalcedony/Flint)
Microcrystalline Quartz (SiO2)
Sandstone
Arenite
Tumbled jasper (likely brecciated or orbicular jasper)
Microcrystalline quartz (SiO₂), with iron-oxide inclusions
Grey Chert River Pebble
Microcrystalline Quartz (SiO2)
Chalcedony (Agate/Carnelian variant)
Silicon Dioxide (SiO2)
Weathered volcanic rock, likely vesicular basalt or scoria
Basaltic volcanic rock; predominantly plagioclase, pyroxene, and possibly olivine with iron-oxide weathering
Reddish sandstone
Quartz-rich sandstone (arenite), commonly iron-oxide stained
Iron-rich breccia (likely hematite–goethite breccia)
Hematite (Fe₂O₃) and goethite (FeO(OH)) in a silicified or iron-cemented breccia
Banded gneiss pebble
Gneiss, commonly quartz–feldspar–mica gneiss
Chert / Flint
Cryptocrystalline Quartz (Silicon Dioxide, SiO2)
Sandstone (Ferruginous)
Clastic sedimentary rock (primarily SiO2 with Fe2O3 cement)
Chert (Jasper/Flint variety)
Silicon Dioxide (SiO2)
Chert (Field Stone)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert
Microcrystalline quartz (SiO2)
Chert (also known as Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Fossiliferous limestone
Calcarenite/bioclastic limestone, predominantly calcite (CaCO₃)
Ferruginous Sandstone
Sandstone (enriched with Iron Oxide)
Sandstone (Quartz-rich Pebble)
Arenite (primarily SiO2)
Petrified Wood
Silicified Wood (Quartzo-feldspathic fossil wood)
Weathered limestone or calcitic fossil/reef fragment
Calcite-rich limestone (CaCO₃), possibly fossiliferous limestone
Chert (Flint)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Ironstone Concretion / Goethite-Hematite Nodule
Goethite/Hematite (α-FeO(OH) / Fe2O3)
Laterite
Laterite (Iron and aluminum-rich residual rock)
Ventifact
Eolian Ventifact (often composed of basalt, chert, or quartzite)
Weathered sandstone or arkosic sandstone
Clastic sandstone, likely quartz–feldspar-rich (arkose)
Chert (Jasper/Agate variety)
Silicon Dioxide (SiO2)
Chert (Banded)
Chert (Microcrystalline Silicon Dioxide, SiO2)
Quartz Arenite / Sandstone
Quartz sandstone (SiO2 rich clastic sedimentary rock)
Chert (Jasper variation)
Silicon Dioxide (SiO2)
Sandstone
Arenite (composed primarily of SiO2)
Precious Opal in Matrix
Hydrated Silica (SiO2·nH2O)
Chert (Flint Nodule)
Microcrystalline Quartz (SiO2)
Sandstone (Red / Iron-stained)
Sandstone (composed predominantly of SiO2 with Fe2O3 cement)
Chert (Green River Chert)
Microcrystalline Quartz (SiO2)
Weathered river pebble, likely quartz-rich sandstone or iron-stained quartzite
Provisional identification: quartz-rich sandstone/quartzite; exact composition cannot be confirmed from the image
Petrified Wood
Silicified Wood (SiO2)
Chert
Microcrystalline Quartz (SiO2)
Leopard Skin Jasper
Orbicular Rhyolite (Silicon Dioxide with various impurities)
Red Sandstone
Arenite (Ferruginous Sandstone)
Flint Pebble
Silicon dioxide (microcrystalline quartz / chalcedony)