Rock Identifier

Category

Igneous Or Sedimentary (Water Worn)

Browse igneous or sedimentary (water worn) specimens identified by the Rock Identifier community.

Opal (Hydrated silica (SiO2·nH2O)) — mineraloid

Opal

Hydrated silica (SiO2·nH2O)

River Stone (likely Basalt or Chert) (Silicon Dioxide (SiO2) for chert or Mafic Extrusive Rock for basalt) — igneous/sedimentary

River Stone (likely Basalt or Chert)

Silicon Dioxide (SiO2) for chert or Mafic Extrusive Rock for basalt

igneous/sedimentary

Greywacke with Quartz Veins (Lithic Sandstone (Greywacke) with SiO2 inclusions) — sedimentary

Greywacke with Quartz Veins

Lithic Sandstone (Greywacke) with SiO2 inclusions

Sandstone (Arenite (primarily SiO2)) — sedimentary

Sandstone

Arenite (primarily SiO2)

Chert (Jasper/Quartzite variety) (Microcrystalline Silica (SiO2)) — sedimentary

Chert (Jasper/Quartzite variety)

Microcrystalline Silica (SiO2)

Hag Stone (Banded Chert or Limestone with Borehole) (Microcrystalline Quartz (Chert) or Calciferous Siltstone (CaCO3/SiO2)) — sedimentary

Hag Stone (Banded Chert or Limestone with Borehole)

Microcrystalline Quartz (Chert) or Calciferous Siltstone (CaCO3/SiO2)

River Pebbles (Tumbled Quartz and Basalt) (Silicon Dioxide (SiO2) for white quartz; Mafic Volcanic Rock for basalt) — igneous and sedimentary

River Pebbles (Tumbled Quartz and Basalt)

Silicon Dioxide (SiO2) for white quartz; Mafic Volcanic Rock for basalt

igneous and sedimentary

Moss Agate (Silicon Dioxide (SiO2) with inclusions) — mineral

Moss Agate

Silicon Dioxide (SiO2) with inclusions

Quartzite (Quartzite (primarily SiO2)) — metamorphic

Quartzite

Quartzite (primarily SiO2)

Obsidian (Volcanic Glass (SiO2 + impurities)) — igneous

Obsidian

Volcanic Glass (SiO2 + impurities)

Quartzite (Quartzite (SiO2)) — metamorphic

Quartzite

Quartzite (SiO2)

Jasper (Iron-stained Chalcedony) (SiO2 with Fe2O3 (Iron Oxide) impurities) — Sedimentary / Mineral (Silica)

Jasper (Iron-stained Chalcedony)

SiO2 with Fe2O3 (Iron Oxide) impurities

Sedimentary / Mineral (Silica)

Painted River Pebble (likely Basalt or Greywacke) (Aphanitic Lithic Clast with Anthropogenic Pigment coating) — Sedimentary or Igneous

Painted River Pebble (likely Basalt or Greywacke)

Aphanitic Lithic Clast with Anthropogenic Pigment coating

Sedimentary or Igneous

Milky Quartz (Silicon Dioxide (SiO2)) — mineral

Milky Quartz

Silicon Dioxide (SiO2)

Dalmatian Jasper (Aplite with Arfvedsonite inclusions) — igneous

Dalmatian Jasper

Aplite with Arfvedsonite inclusions

Shale (Shale (Consolidated fine-grained clay/silt)) — sedimentary

Shale

Shale (Consolidated fine-grained clay/silt)

Chert (variant of Flint) (Chert (SiO2)) — Sedimentary

Chert (variant of Flint)

Chert (SiO2)

Halite (Rock Salt) (Halite (Sodium Chloride, NaCl)) — mineral

Halite (Rock Salt)

Halite (Sodium Chloride, NaCl)

Quartz Pebble (Water-worn Quartzite) (Silicon Dioxide (SiO2)) — metamorphic

Quartz Pebble (Water-worn Quartzite)

Silicon Dioxide (SiO2)

Milky Quartz (Water-worn Pebble) (Silicon Dioxide (SiO2)) — mineral

Milky Quartz (Water-worn Pebble)

Silicon Dioxide (SiO2)

River Quartzite (Water-worn Quartzite) (Quartzite (primarily SiO2)) — metamorphic

River Quartzite (Water-worn Quartzite)

Quartzite (primarily SiO2)

Garnetiferous Pegmatite (Pegmatite with Almandine Garnet and Muscovite) — igneous

Garnetiferous Pegmatite

Pegmatite with Almandine Garnet and Muscovite

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Porphyritic Andesite/Basalt or Diorite River Rock (Porphyritic Igneous Rock) — Igneous

Porphyritic Andesite/Basalt or Diorite River Rock

Porphyritic Igneous Rock

Granite or Porphyritic Igneous Rock (weathered) (Granitoid) — Igneous

Granite or Porphyritic Igneous Rock (weathered)

Granitoid

Sandstone (likely Quartzose Sandstone) (Arenite (primarily SiO2)) — sedimentary

Sandstone (likely Quartzose Sandstone)

Arenite (primarily SiO2)

River Rock (Basalt/Greywacke pebbles) (Fluvial gravel primarily composed of Mafic Volcanic Rock (Basalt) or Lithic Sandstone (Greywacke)) — igneous and sedimentary

River Rock (Basalt/Greywacke pebbles)

Fluvial gravel primarily composed of Mafic Volcanic Rock (Basalt) or Lithic Sandstone (Greywacke)

igneous and sedimentary

River Quartz Cobble (Silicon Dioxide (SiO2)) — mineral

River Quartz Cobble

Silicon Dioxide (SiO2)

Hag Stone (Flint / Chert / Limestone concretion with a natural hole) — sedimentary

Hag Stone

Flint / Chert / Limestone concretion with a natural hole

Milky Quartz (Water-Worn Pebble) (Quartz (Silicon Dioxide, SiO2)) — mineral

Milky Quartz (Water-Worn Pebble)

Quartz (Silicon Dioxide, SiO2)

Magnetite (Iron(II,III) oxide (Fe3O4)) — mineral

Magnetite

Iron(II,III) oxide (Fe3O4)

Agate Geode (Chalcedony (SiO2 - Silicon Dioxide)) — sedimentary (secondary mineral formation)

Agate Geode

Chalcedony (SiO2 - Silicon Dioxide)

sedimentary (secondary mineral formation)

Amethyst (Rough) (Silicon Dioxide with iron impurities (SiO2)) — mineral

Amethyst (Rough)

Silicon Dioxide with iron impurities (SiO2)

Sandstone Grain (Clastic Sedimentary Rock Grain (SiO2 dominated)) — sedimentary

Sandstone Grain

Clastic Sedimentary Rock Grain (SiO2 dominated)

Limestone with Calcite Veins (Sedimentary Calcium Carbonate (CaCO3)) — sedimentary

Limestone with Calcite Veins

Sedimentary Calcium Carbonate (CaCO3)

Riverstone Jasper (Chalcedony) (Silicon Dioxide (SiO2)) — sedimentary

Riverstone Jasper (Chalcedony)

Silicon Dioxide (SiO2)

Garnet (Red Garnet) (Garnet Group. The red varieties seen in jewelry are typically Almandine (Fe3Al2(SiO4)3), Pyrope (Mg3Al2(SiO4)3), or a mix of the two (pyrope-almandine series).) — Mineral (specifically, a variety of the mineral species Pyrope-Almandine Garnet)

Garnet (Red Garnet)

Garnet Group. The red varieties seen in jewelry are typically Almandine (Fe3Al2(SiO4)3), Pyrope (Mg3Al2(SiO4)3), or a mix of the two (pyrope-almandine series).

Mineral (specifically, a variety of the mineral species Pyrope-Almandine Garnet)

Sandstone (Arenite) — Sedimentary

Sandstone

Arenite

Amber / Copal (Fossilized Tree Resin (Succinate)) — Mineraloid

Amber / Copal

Fossilized Tree Resin (Succinate)

Quartz Pebble (Iron-stained) (Silicon Dioxide (SiO2)) — Mineral / Sedimentary setting

Quartz Pebble (Iron-stained)

Silicon Dioxide (SiO2)

Mineral / Sedimentary setting

Pink Quartzite (Quartzite (SiO2 with iron oxide inclusions)) — metamorphic

Pink Quartzite

Quartzite (SiO2 with iron oxide inclusions)

Ferruginous Quartz (Silicon Dioxide (SiO2) with Iron Oxide (Hematite/Limonite) inclusions) — mineral

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide (Hematite/Limonite) inclusions