Rock Identifier

Category

Organic Gemstone (Not A Rock)

Browse organic gemstone (not a rock) specimens identified by the Rock Identifier community.

Limestone (River Pebble) (Sedimentary Calcium Carbonate (CaCO3)) — sedimentary

Limestone (River Pebble)

Sedimentary Calcium Carbonate (CaCO3)

Bauxite (AlOx(OH)3-2x (mixture of Gibbsite, Boehmite, and Diaspore)) — sedimentary

Bauxite

AlOx(OH)3-2x (mixture of Gibbsite, Boehmite, and Diaspore)

Quartzite (Quartzite (principally SiO2)) — metamorphic

Quartzite

Quartzite (principally SiO2)

Arkosic Sandstone (or Conglomeritic Sandstone fragment) (Arkose (rich in feldspar)) — sedimentary

Arkosic Sandstone (or Conglomeritic Sandstone fragment)

Arkose (rich in feldspar)

Quartzite (Quartzite (SiO2)) — metamorphic

Quartzite

Quartzite (SiO2)

Sandstone (Arenite (composed primarily of SiO2)) — sedimentary

Sandstone

Arenite (composed primarily of SiO2)

Bumblebee Jasper (Fossiliferous Calcite containing Orpiment and Realgar) — sedimentary

Bumblebee Jasper

Fossiliferous Calcite containing Orpiment and Realgar

Slag (Anthropogenic glassy silicate) — Mineral-like byproduct

Slag

Anthropogenic glassy silicate

Mineral-like byproduct

River Rock (likely Quartzite or Quartz-rich Siltstone) (Quartzite (SiO2)) — metamorphic

River Rock (likely Quartzite or Quartz-rich Siltstone)

Quartzite (SiO2)

Quartzite (Iron-stained) (Quartzite (mostly SiO2)) — metamorphic

Quartzite (Iron-stained)

Quartzite (mostly SiO2)

Hematite (Iron(III) oxide (Fe2O3)) — mineral

Hematite

Iron(III) oxide (Fe2O3)

River Siltstone / Mudstone Pebble (Siltstone (composed of mixed silicate and carbonate minerals)) — sedimentary

River Siltstone / Mudstone Pebble

Siltstone (composed of mixed silicate and carbonate minerals)

Pyrite in Matrix (Commonly called Fool's Gold) (Iron Sulfide (FeS2)) — mineral

Pyrite in Matrix (Commonly called Fool's Gold)

Iron Sulfide (FeS2)

Green Fluorite in Host Rock (Fluorite (Calcium Fluoride, CaF2)) — mineral

Green Fluorite in Host Rock

Fluorite (Calcium Fluoride, CaF2)

Dyed Pumice (Vesicular Rhyolite (Artificial Coloration Addition)) — igneous

Dyed Pumice

Vesicular Rhyolite (Artificial Coloration Addition)

Limonite / Ironstone Nodule (Limonite (Hydrated iron(III) oxide-hydroxide), FeO(OH)·nH2O) — mineral

Limonite / Ironstone Nodule

Limonite (Hydrated iron(III) oxide-hydroxide), FeO(OH)·nH2O

Obsidian (Obsidian (Volcanic Glass) SiO2 (70% or more)) — igneous

Obsidian

Obsidian (Volcanic Glass) SiO2 (70% or more)

Quartzite Pebble (Quartzite (SiO2)) — metamorphic

Quartzite Pebble

Quartzite (SiO2)

Quartzite (Pink/Red variety) (Quartzite (SiO2 with iron oxide impurities)) — metamorphic

Quartzite (Pink/Red variety)

Quartzite (SiO2 with iron oxide impurities)

Desert Rose (also known as Sand Rose) (Gypsum (CaSO4·2H2O) or Barite (BaSO4) with sand inclusions) — mineral

Desert Rose (also known as Sand Rose)

Gypsum (CaSO4·2H2O) or Barite (BaSO4) with sand inclusions

Granite (Phaneritic Plutonic Igneous Rock (composed of quartz, alkali feldspar, and plagioclase)) — igneous

Granite

Phaneritic Plutonic Igneous Rock (composed of quartz, alkali feldspar, and plagioclase)

Schist (Chlorite/Mica Schist) — metamorphic

Schist

Chlorite/Mica Schist

Ferruginous Sandstone (Sandstone (arenite) with Limonite/Goethite cement) — sedimentary

Ferruginous Sandstone

Sandstone (arenite) with Limonite/Goethite cement

Carnelian Agate (Carnelian (Silicon Dioxide - SiO2)) — mineral

Carnelian Agate

Carnelian (Silicon Dioxide - SiO2)

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

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Carnelian Agate (Silicon Dioxide (SiO2) with Iron Oxide impurities) — mineral

Carnelian Agate

Silicon Dioxide (SiO2) with Iron Oxide impurities

Amethyst (Raw Quartz) (Silicon Dioxide (SiO2)) — mineral

Amethyst (Raw Quartz)

Silicon Dioxide (SiO2)

Carnelian (SiO2 (Silicon Dioxide) - Carnelian Agate/Chalcedony) — mineral

Carnelian

SiO2 (Silicon Dioxide) - Carnelian Agate/Chalcedony

Quartz (likely Herkimer Diamond style) (Silicon Dioxide (SiO2)) — mineral

Quartz (likely Herkimer Diamond style)

Silicon Dioxide (SiO2)

Chert (with Limestone/Dolomite host) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (with Limestone/Dolomite host)

Microcrystalline Quartz (SiO2)

Chert (Chert (SiO2)) — sedimentary

Chert

Chert (SiO2)

Petrified Wood (Silicified Wood (SiO2 - primarily Quartz/Chalcedony/Opal)) — Mineral/Fossil (Sedimentary context)

Petrified Wood

Silicified Wood (SiO2 - primarily Quartz/Chalcedony/Opal)

Mineral/Fossil (Sedimentary context)

Limonite (Iron Ore) (FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide)) — mineral

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide)

Red Agate (Carnelian) (Chalcedony (SiO2) with iron oxide inclusions) — mineral

Red Agate (Carnelian)

Chalcedony (SiO2) with iron oxide inclusions

Wild Horse Magnesite (Magnesite with Hematite inclusions (MgCO3)) — mineral

Wild Horse Magnesite

Magnesite with Hematite inclusions (MgCO3)

Carnelian (a variety of Chalcedony) (SiO2 (Silicon Dioxide with Iron Oxide impurities)) — mineral

Carnelian (a variety of Chalcedony)

SiO2 (Silicon Dioxide with Iron Oxide impurities)

Limonite (Iron Ore) (Limonite; FeO(OH)·nH2O) — mineral

Limonite (Iron Ore)

Limonite; FeO(OH)·nH2O

Smoky Quartz (Tumbled) (Smoky Quartz (Silicon Dioxide - SiO2)) — mineral

Smoky Quartz (Tumbled)

Smoky Quartz (Silicon Dioxide - SiO2)

Rough Amethyst Quartz (Silicon Dioxide with Iron impurities (SiO2)) — mineral

Rough Amethyst Quartz

Silicon Dioxide with Iron impurities (SiO2)

Quartzite (Quartzite (SiO2)) — metamorphic

Quartzite

Quartzite (SiO2)

Carnelian (Carnelian Agate) (Silicon dioxide (SiO2) - a variety of Chalcedony) — mineral

Carnelian (Carnelian Agate)

Silicon dioxide (SiO2) - a variety of Chalcedony

Gold Nugget (Native Gold (Au)) — mineral

Gold Nugget

Native Gold (Au)