Rock Identifier

Category

Organic (Non Geological)

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

Obsidian (Obsidian (Volcanic Glass)) — igneous

Obsidian

Obsidian (Volcanic Glass)

Rounded brown chert (flint) pebble (Microcrystalline quartz (SiO₂), commonly with iron-oxide staining) — sedimentary

Rounded brown chert (flint) pebble

Microcrystalline quartz (SiO₂), commonly with iron-oxide staining

Rose quartz (Quartz (SiO₂), pink variety) — mineral

Rose quartz

Quartz (SiO₂), pink variety

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

Chert Nodule (Flint)

Silicon Dioxide (SiO2)

Obsidian (Volcanic glass) — igneous

Obsidian

Volcanic glass

Black Obsidian (Amorphous volcanic glass (SiO2 + impurities)) — igneous

Black Obsidian

Amorphous volcanic glass (SiO2 + impurities)

Cultured pearls (Pearl; predominantly aragonite (CaCO₃) in nacre with organic conchiolin) — gemstone

Cultured pearls

Pearl; predominantly aragonite (CaCO₃) in nacre with organic conchiolin

Dendritic jasper/chalcedony (Silica-rich microcrystalline quartz (SiO₂) with manganese-oxide dendrites) — mineral

Dendritic jasper/chalcedony

Silica-rich microcrystalline quartz (SiO₂) with manganese-oxide dendrites

Dark metamorphic rock, likely biotite schist or gneiss (Quartz–feldspar–biotite metamorphic rock; exact identification requires a fresh surface and testing) — metamorphic

Dark metamorphic rock, likely biotite schist or gneiss

Quartz–feldspar–biotite metamorphic rock; exact identification requires a fresh surface and testing

Obsidian (Obsidian (volcanic glass), amorphous SiO2 + impurities) — igneous

Obsidian

Obsidian (volcanic glass), amorphous SiO2 + impurities

Quartzite with Iron Oxide Vein (Metamorphic Quartzite (SiO2 with Hematite/Limonite impurities)) — metamorphic

Quartzite with Iron Oxide Vein

Metamorphic Quartzite (SiO2 with Hematite/Limonite impurities)

Black obsidian (probable) (Volcanic glass; primarily SiO₂-rich rhyolitic composition) — igneous

Black obsidian (probable)

Volcanic glass; primarily SiO₂-rich rhyolitic composition

Green aventurine bead bracelet (Quartz (SiO₂), typically green aventurine containing fuchsite mica or other chromium-bearing inclusions) — mineral

Green aventurine bead bracelet

Quartz (SiO₂), typically green aventurine containing fuchsite mica or other chromium-bearing inclusions

Quartzite (Metamorphic Quartzite (SiO2)) — metamorphic

Quartzite

Metamorphic Quartzite (SiO2)

Porous limestone fragment (Calcite-rich limestone (CaCO₃), possibly bioclastic limestone) — sedimentary

Porous limestone fragment

Calcite-rich limestone (CaCO₃), possibly bioclastic limestone

Tumbled moss agate (Chalcedony (microcrystalline quartz, SiO₂) with moss-like inclusions) — mineral

Tumbled moss agate

Chalcedony (microcrystalline quartz, SiO₂) with moss-like inclusions

Chert (varieties: Flint or Chalcedony) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (varieties: Flint or Chalcedony)

Microcrystalline Quartz (SiO2)

Glendonite (Calcite Pseudomorph after Ikaite) (Calcite (CaCO3) pseudomorph after Ikaite (CaCO3·6H2O)) — mineral

Glendonite (Calcite Pseudomorph after Ikaite)

Calcite (CaCO3) pseudomorph after Ikaite (CaCO3·6H2O)

Fine-grained gray stone, likely slate or weathered basalt (Indeterminate; possible slate (foliated phyllite-grade shale)) — metamorphic

Fine-grained gray stone, likely slate or weathered basalt

Indeterminate; possible slate (foliated phyllite-grade shale)

Banded agate (likely petrified wood or silicified sediment) (Microcrystalline quartz/chalcedony, SiO₂; possible silicified wood) — sedimentary

Banded agate (likely petrified wood or silicified sediment)

Microcrystalline quartz/chalcedony, SiO₂; possible silicified wood

Yellow calcite crystal specimen (Calcite (CaCO₃), likely honey/yellow calcite) — mineral

Yellow calcite crystal specimen

Calcite (CaCO₃), likely honey/yellow calcite

Botryoidal pyrite (likely with quartz or chlorite matrix) (Pyrite, FeS₂; botryoidal aggregate) — mineral

Botryoidal pyrite (likely with quartz or chlorite matrix)

Pyrite, FeS₂; botryoidal aggregate

Jasper (Silicon Dioxide (Microcrystalline Quartz, $SiO_2$)) — sedimentary

Jasper

Silicon Dioxide (Microcrystalline Quartz, $SiO_2$)

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

Chert (Flint)

Microcrystalline Quartz (SiO2)

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

Chert (and/or Flint)

Microcrystalline or cryptocrystalline Quartz (SiO2)

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

Chert (variant Flint)

Silicon Dioxide (SiO2)

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

Sandstone

Arenite (primarily composed of SiO2)

Chert (Red Jasper variant) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Red Jasper variant)

Microcrystalline Quartz (SiO2)

Chert (specifically Yellow/Brown Chert or Flint) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (specifically Yellow/Brown Chert or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Pyrite-bearing Schist (Pyritic Quartz-Mica Schist with FeS2 inclusion) — metamorphic

Pyrite-bearing Schist

Pyritic Quartz-Mica Schist with FeS2 inclusion

Chert (Jasper/Common Opal transition) (Microcrystalline Quartz (SiO2) with iron oxide inclusions) — sedimentary

Chert (Jasper/Common Opal transition)

Microcrystalline Quartz (SiO2) with iron oxide inclusions

Chert (Flint variety) (Chert (Microcrystalline or Cryptocrystalline Quartz), SiO2) — sedimentary

Chert (Flint variety)

Chert (Microcrystalline or Cryptocrystalline Quartz), SiO2

Mahogany Obsidian (Obsidian (Volcanic Glass with Hematite inclusions)) — igneous

Mahogany Obsidian

Obsidian (Volcanic Glass with Hematite inclusions)

Black Obsidian (Volcanic Glass (SiO2 with impurities)) — igneous

Black Obsidian

Volcanic Glass (SiO2 with impurities)

Likely tumbled dark volcanic rock (Probably basalt or fine-grained andesite; exact identification requires testing) — igneous

Likely tumbled dark volcanic rock

Probably basalt or fine-grained andesite; exact identification requires testing

Chert Nodule / Ironstone Concretion (Microcrystalline Quartz (SiO2) with Iron Oxides) — sedimentary

Chert Nodule / Ironstone Concretion

Microcrystalline Quartz (SiO2) with Iron Oxides

Obsidian (Black Obsidian) (Obsidian (Volcanic Glass)) — igneous

Obsidian (Black Obsidian)

Obsidian (Volcanic Glass)

Botryoidal chalcedony/geode fragment (Microcrystalline quartz, SiO₂, likely chalcedony with drusy quartz) — mineral

Botryoidal chalcedony/geode fragment

Microcrystalline quartz, SiO₂, likely chalcedony with drusy quartz

Honey calcite (orange calcite) (Calcite, calcium carbonate (CaCO₃)) — mineral

Honey calcite (orange calcite)

Calcite, calcium carbonate (CaCO₃)

Yellow calcite crystal (Calcite (CaCO₃), likely honey/yellow calcite) — mineral

Yellow calcite crystal

Calcite (CaCO₃), likely honey/yellow calcite

Fine-grained brown sand or weathered soil (Unconsolidated siliciclastic sediment, likely quartz-rich sand (SiO₂) mixed with iron-oxide-coated grains) — sedimentary

Fine-grained brown sand or weathered soil

Unconsolidated siliciclastic sediment, likely quartz-rich sand (SiO₂) mixed with iron-oxide-coated grains

Coquina Limestone (Fossiliferous Limestone) (Calcareous bioclastic sedimentary rock (CaCO3)) — sedimentary

Coquina Limestone (Fossiliferous Limestone)

Calcareous bioclastic sedimentary rock (CaCO3)