Rock Identifier

Category

Organic (Often Found By Beachcombers)

Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.

Milky Quartz (Quartz (Silicon Dioxide - SiO2)) — mineral

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Gneiss (Gneiss) — metamorphic

Gneiss

Gneiss

Jasper (Iron-stained Chert) (Silicon Dioxide (SiO2) with impurities of Iron Oxide) — sedimentary

Jasper (Iron-stained Chert)

Silicon Dioxide (SiO2) with impurities of Iron Oxide

Rose Quartz (Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese) — mineral

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Amazonite (KAlSi3O8 (Potassium Aluminum Silicate)) — mineral

Amazonite

KAlSi3O8 (Potassium Aluminum Silicate)

Chert (Flint Nodules) (Chert (Cryptocrystalline variety of Quartz, SiO2)) — sedimentary

Chert (Flint Nodules)

Chert (Cryptocrystalline variety of Quartz, SiO2)

Geode (Unopened) (Silica Concretion / Geode (Formula: SiO2 for quartz internal contents)) — sedimentary

Geode (Unopened)

Silica Concretion / Geode (Formula: SiO2 for quartz internal contents)

Greisen (Greisen) — Metamorphic

Greisen

Greisen

Smoky Quartz (Silicon Dioxide (SiO2)) — mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Quartz (Variety: Citrine or Tumbled Chalcedony) (Silicon Dioxide (SiO2)) — mineral

Quartz (Variety: Citrine or Tumbled Chalcedony)

Silicon Dioxide (SiO2)

Fuchsite (Chrome Mica) (K(Al,Cr)2(AlSi3O10)(OH)2) — mineral

Fuchsite (Chrome Mica)

K(Al,Cr)2(AlSi3O10)(OH)2

Pyrite (Fool's Gold) (Iron Sulfide (FeS2)) — mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Granite (Granite (Felsic Plutonic Rock)) — igneous

Granite

Granite (Felsic Plutonic Rock)

Fossilized Sea Urchin (Echinoid) (Echinoidea (Class); commonly Clypeasteroida for sand dollar types) — sedimentary (fossil)

Fossilized Sea Urchin (Echinoid)

Echinoidea (Class); commonly Clypeasteroida for sand dollar types

sedimentary (fossil)

Quartz (Yellow/Citrine variety) (Crystalline Silicon Dioxide (SiO2)) — mineral

Quartz (Yellow/Citrine variety)

Crystalline Silicon Dioxide (SiO2)

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

Agate (Chalcedony)

Agate (Silicon Dioxide - SiO2)

Bauxite (Bauxite (Al2O3·2H2O)) — sedimentary

Bauxite

Bauxite (Al2O3·2H2O)

Jasper with Epidote (Unakite-related) (Epidotized Quartzite (composed of Quartz, Epidote, and Feldspar)) — metamorphic

Jasper with Epidote (Unakite-related)

Epidotized Quartzite (composed of Quartz, Epidote, and Feldspar)

Amazonite (Potassium aluminum silicate (KAlSi3O8)) — mineral

Amazonite

Potassium aluminum silicate (KAlSi3O8)

Polished Chert (Flint) (Silicon Dioxide (SiO2)) — sedimentary

Polished Chert (Flint)

Silicon Dioxide (SiO2)

Travertine (Terrestrial Sedimentary Limestone (CaCO3)) — sedimentary

Travertine

Terrestrial Sedimentary Limestone (CaCO3)

Quartz / Common Opal Transition (Silicon Dioxide (SiO2)) — mineral

Quartz / Common Opal Transition

Silicon Dioxide (SiO2)

Wishing Stone with Quartz Vein (Hydrothermal Quartz Vein in Metasedimentary Matrix (primarily SiO2)) — metamorphic

Wishing Stone with Quartz Vein

Hydrothermal Quartz Vein in Metasedimentary Matrix (primarily SiO2)

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

Carnelian Agate

Chalcedony (SiO2) with iron oxide inclusions

Yellow Ocher / Limonite (FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide)) — mineral

Yellow Ocher / Limonite

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

Rose Quartz with Schist Matrix (Silicon Dioxide (SiO2) with Mica-Schist) — mineral

Rose Quartz with Schist Matrix

Silicon Dioxide (SiO2) with Mica-Schist

Ferruginous Sandstone (Arenite with Iron-Oxide cement (primarily Fe2O3 • nH2O)) — sedimentary

Ferruginous Sandstone

Arenite with Iron-Oxide cement (primarily Fe2O3 • nH2O)

Chert (or Flint) (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (or Flint)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Galena (Lead(II) sulfide (PbS)) — mineral

Galena

Lead(II) sulfide (PbS)

Sodalite (Sodalite - Na8(Al6Si6O24)Cl2) — mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

Banded Calcite (often sold as 'Mexican Onyx' or 'Green Onyx') (Calcite (Calcium Carbonate, CaCO3)) — sedimentary

Banded Calcite (often sold as 'Mexican Onyx' or 'Green Onyx')

Calcite (Calcium Carbonate, CaCO3)

Slickenside (Tectonic Fault Scarp Surface) — metamorphic

Slickenside

Tectonic Fault Scarp Surface

Emerald (Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities) — mineral

Emerald

Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities

Amethyst (as a jewelry accent) (Amethyst (Silicon Dioxide SiO2 with Iron impurities)) — mineral

Amethyst (as a jewelry accent)

Amethyst (Silicon Dioxide SiO2 with Iron impurities)

Lepidolite on Pegmatite (Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)) — mineral

Lepidolite on Pegmatite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)

Granite (Phaneritic Plutonic Igneous Rock (Rich in SiO2)) — igneous

Granite

Phaneritic Plutonic Igneous Rock (Rich in SiO2)

Chert (Jasper and Chalcedony) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Jasper and Chalcedony)

Silicon Dioxide (SiO2)

Agate (specifically a Thunderegg/Agate Nodule) (Cryptocrystalline Quartz (SiO2)) — mineral

Agate (specifically a Thunderegg/Agate Nodule)

Cryptocrystalline Quartz (SiO2)

Milky Quartz (Quartz (Silicon Dioxide, SiO2)) — mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Concrete / Conglomerate (Man-made) (Artificial Conglomerate (Cementitious Composite)) — sedimentary

Concrete / Conglomerate (Man-made)

Artificial Conglomerate (Cementitious Composite)

Smoky Quartz and Feldspar Pegmatite (Granitic Pegmatite (chiefly SiO2 and KAlSi3O8)) — igneous

Smoky Quartz and Feldspar Pegmatite

Granitic Pegmatite (chiefly SiO2 and KAlSi3O8)

Milky Quartz (Silicon Dioxide (SiO2)) — mineral

Milky Quartz

Silicon Dioxide (SiO2)