Ammonite Fossil
Ammonoidea (primarily composed of Calcite, CaCO3)
Category
Browse anthropogenic (man made material) specimens identified by the Rock Identifier community.
Ammonite Fossil
Ammonoidea (primarily composed of Calcite, CaCO3)
Sandstone
Arenite (primarily SiO2)
Quartzite Pebble
Quartzite (SiO2)
Sandstone
Arenite (primarily SiO2)
Fire Opal (in Matrix)
Hydrated Silica (SiO2·nH2O)
Red Sandstone
Arenite (Ferruginous Sandstone)
Sandstone (lithic wacke/conglomerate mix)
Clastic Sedimentary Rock (SiO2 with lithic fragments)
Marble
Recrystallized Calcite (CaCO3)
Glacial Erratic (Sandstone/Quartzite)
Glacial Erratic specimen (likely Orthoquartzite or Feldspathic Sandstone)
Siltstone Pebble
Siltstone
Sandstone with Manganese Dendrites
Arenite (mostly SiO2) with Manganese Oxide inclusions (MnO2)
Marble (polished)
Recrystallized Calcite (CaCO3)
Olivine in Basalt
Peridotite / Forsterite ((Mg,Fe)2SiO4)
Sandstone (likely Quartz Sandstone)
Arenite (composed primarily of SiO2)
Sunstone
(Ca,Na)(Al,Si)4O8 (Oligoclase or Andesine)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Geode with Quartz/Chalcedony
Silicon Dioxide (SiO2)
Amazonite
Microcline (KAlSi3O8) with trace lead (Pb)
Fossilized coral or porous marine limestone
Likely fossil coral (Scleractinia), composed mainly of calcite/aragonite (CaCO₃)
Granite
Intrusive Igneous Rock
Slate
Metamorphic Rock (Fine-grained)
Granite
Intrusive Igneous Rock
Nephrite Jade
Nephrite
Jasper
Silicon dioxide (SiO2)
Raw calcite specimen
Calcite, calcium carbonate (CaCO₃)
Chert (Jasper Variant likely)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Limestone (Cliff Formation)
Limestone (predominantly CaCO3 as calcite)
Limestone with Calcite Crust
Sedimentary Calcium Carbonate (CaCO3)
Granite Pebble
Granite (Phaneritic intrusive igneous rock)
Polished quartz-rich pebble, possibly jasper or quartzite
Quartzite or chalcedony-bearing jasper; predominantly SiO₂
Yellow chalcedony (likely heat-treated or resin-coated)
Microcrystalline quartz, SiO₂
Porphyritic granite or granodiorite
Coarse-grained plutonic rock composed mainly of quartz (SiO₂), feldspar, and mica/amphibole
Tumbled chalcedony (likely brown agate/jasper)
Microcrystalline quartz, SiO₂; potentially iron-stained chalcedony or jasper
Quartz-rich rock, possibly milky quartz or quartzite
Quartz (SiO₂), potentially quartzite if the grains are fused
Iron-rich chert or jasper
Microcrystalline quartz (SiO₂), colored by hematite/goethite inclusions
Chert (Common Opal variant)
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Diamond
C (Carbon)
Black Granite (Basalt or Gabbro)
Mafic Igneous Rock (primarily Plagioclase and Pyroxene)
Rose Quartz
SiO2 (Silicon Dioxide)
Drupa or Druzy Quartz on Geode Fragment
Crystalline Silicon Dioxide (SiO2)