Organic (Mineraloid)

Browse organic (mineraloid) specimens identified by the Rock Identifier community.

Fossiliferous Limestone

Sedimentary Calcium Carbonate (CaCO3)

sedimentary

Fossiliferous Limestone

Limestone with fossil inclusions (CaCO3)

sedimentary

Fossilized Brachiopod

Phylum Brachiopoda (replaced by Calcite/CaCO3)

sedimentary

Pumice

Vesicular volcanic glass (primarily SiO2 with Al2O3)

Igneous

Pumice

Pumicite (Amorphous glass with varying chemical composition, often rhyolitic)

Igneous

Aragonite

Aragonite (CaCO3)

mineral

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Sedimentary rock

Granite (likely a river or beach pebble)

Granite (a felsic intrusive igneous rock primarily composed of quartz, feldspar, and mica)

Igneous

Fossil Sand Dollar (Echinoidea)

Phylum Echinodermata, Class Echinoidea (likely Dendraster or Scutella)

sedimentary

Fossilized Brachiopod

Brachiopoda (Class Rhynchonellata or Spiriferida)

sedimentary

Magnetite

Magnetite (Fe3O4)

Mineral

Pumice

Pumice (volcanic rock)

Igneous

Jasper (Mookaite style)

Jasper (Silica-rich Microcrystalline Quartz, SiO2)

sedimentary

Botryoidal Hematite (Kidney Ore)

Hematite (Fe2O3)

mineral

Chert (Field Stone)

Microcrystalline Quartz (SiO2)

sedimentary

Chert (Flint variety)

Silicon Dioxide (SiO2)

sedimentary

Hypersthene (or Enstatite/Ferrosilite)

Orthopyroxene series (Mg,Fe)SiO3 - specifically, historically hypersthene (intermediate member) now referred to as Enstatite (Mg-rich) or Ferrosilite (Fe-rich)

Mineral