Rock Identifier

Category

Sedimentary (Volcanic)

Browse sedimentary (volcanic) specimens identified by the Rock Identifier community.

Olivine (Peridotite) (Magnesium Iron Silicate - (Mg, Fe)2SiO4) — igneous

Olivine (Peridotite)

Magnesium Iron Silicate - (Mg, Fe)2SiO4

Obsidian (Obsidian (volcanic glass; primarily SiO2)) — igneous

Obsidian

Obsidian (volcanic glass; primarily SiO2)

Basalt (Water-worn pebble) (Basalt (Aphanitic mafic volcanic rock)) — igneous

Basalt (Water-worn pebble)

Basalt (Aphanitic mafic volcanic rock)

Sandstone (Arenite (primarily SiO2)) — sedimentary

Sandstone

Arenite (primarily SiO2)

Satin Spar (Gypsum) (Hydrous Calcium Sulfate (CaSO4·2H2O)) — mineral

Satin Spar (Gypsum)

Hydrous Calcium Sulfate (CaSO4·2H2O)

Silver Sheen Obsidian (Volcanic Glass (Amorphous Silicon Dioxide - SiO2 with impurities)) — igneous

Silver Sheen Obsidian

Volcanic Glass (Amorphous Silicon Dioxide - SiO2 with impurities)

Basalt (Mafic volcanic rock (Primarily Plagioclase Feldspar and Pyroxene)) — Igneous

Basalt

Mafic volcanic rock (Primarily Plagioclase Feldspar and Pyroxene)

Snowflake Obsidian (Vitreous volcanic silicate rock (SiO2) with Spherulite inclusions) — igneous

Snowflake Obsidian

Vitreous volcanic silicate rock (SiO2) with Spherulite inclusions

Obsidian (Black) (Obsidian (approx. 70–75% SiO2)) — igneous

Obsidian (Black)

Obsidian (approx. 70–75% SiO2)

Obsidian (specifically Mahogany Obsidian) (Volcanic glass (high silica content, SiO2)) — igneous

Obsidian (specifically Mahogany Obsidian)

Volcanic glass (high silica content, SiO2)

Apache Tears (Obsidian) (Hydrated Volcanic Glass (Amorphous SiO2 + H2O)) — igneous

Apache Tears (Obsidian)

Hydrated Volcanic Glass (Amorphous SiO2 + H2O)

Obsidian (Obsidian (Volcanic Glass), primarily SiO2 (70% or more silicon dioxide)) — Igneous

Obsidian

Obsidian (Volcanic Glass), primarily SiO2 (70% or more silicon dioxide)

Obsidian Arrowhead (Volcanic Glass (70% or more SiO2)) — Igneous

Obsidian Arrowhead

Volcanic Glass (70% or more SiO2)

Crazy Lace Agate (Silicon dioxide (SiO2) - a variety of banded Chalcedony (cryptocrystalline quartz)) — mineral

Crazy Lace Agate

Silicon dioxide (SiO2) - a variety of banded Chalcedony (cryptocrystalline quartz)

Orbicular Jasper (Silicon Dioxide (SiO2), variety of Chalcedony) — Mineral

Orbicular Jasper

Silicon Dioxide (SiO2), variety of Chalcedony

Agate (Agate (Silicon Dioxide, SiO2)) — mineral

Agate

Agate (Silicon Dioxide, SiO2)

Amygdaloidal Basalt (Amygdaloidal Basalt (Mafic Volcanic Rock)) — Igneous

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic Volcanic Rock)

Obsidian (Volcanic Glass (Primary component: SiO2)) — igneous

Obsidian

Volcanic Glass (Primary component: SiO2)

Basalt (Basalt) — Igneous

Basalt

Basalt

Black Obsidian (Volcanic Glass (SiO2 + impurities like Fe3O4)) — igneous

Black Obsidian

Volcanic Glass (SiO2 + impurities like Fe3O4)

Obsidian (Volcanic Glass (Amorphous Silicon Dioxide, SiO2)) — igneous

Obsidian

Volcanic Glass (Amorphous Silicon Dioxide, SiO2)

Basalt with Quartz/Calcite Vein (Basalt (Mafic Volcanic Rock with secondary mineralization)) — igneous

Basalt with Quartz/Calcite Vein

Basalt (Mafic Volcanic Rock with secondary mineralization)

Scoria (Vesicular Basalt) (Scoria (Extrusive Igneous Rock)) — igneous

Scoria (Vesicular Basalt)

Scoria (Extrusive Igneous Rock)

Olivine (Peridotite) ((Mg,Fe)2SiO4 (Magnesium Iron Silicate)) — igneous

Olivine (Peridotite)

(Mg,Fe)2SiO4 (Magnesium Iron Silicate)

Prehnite (Prehnite - Ca2Al(AlSi3O10)(OH)2) — mineral

Prehnite

Prehnite - Ca2Al(AlSi3O10)(OH)2

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

Amethyst

SiO2 (Silicon Dioxide with iron impurities)

Prehnite (Prehnite (Ca2Al2Si3O10(OH)2)) — mineral

Prehnite

Prehnite (Ca2Al2Si3O10(OH)2)

Carnelian (Red Chalcedony) (Silicon Dioxide (SiO2) with iron oxide impurities) — mineral

Carnelian (Red Chalcedony)

Silicon Dioxide (SiO2) with iron oxide impurities

Brimstone (Native Sulfur) (Native Sulfur (S)) — mineral

Brimstone (Native Sulfur)

Native Sulfur (S)

Prehnite (Prehnite (Ca2Al2Si3O10(OH)2)) — mineral

Prehnite

Prehnite (Ca2Al2Si3O10(OH)2)

Blue Chalcedony (Chalcedony (SiO2)) — mineral

Blue Chalcedony

Chalcedony (SiO2)

Ocean Jasper (Orbicular Jasper (Silicon Dioxide, SiO2)) — mineral

Ocean Jasper

Orbicular Jasper (Silicon Dioxide, SiO2)

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

Carnelian Agate

Silicon Dioxide (SiO2) with Iron Oxide impurities

Gold Nugget (Native Gold (Au)) — mineral

Gold Nugget

Native Gold (Au)

Diamond in Kimberlite (Diamond in Kimberlite Matrix (Diamond: C, Kimberlite: complex Potassic Peridotite)) — igneous

Diamond in Kimberlite

Diamond in Kimberlite Matrix (Diamond: C, Kimberlite: complex Potassic Peridotite)

Banded Agate (Pink/White) (Silicon Dioxide (SiO2) - Variety of Chalcedony) — mineral

Banded Agate (Pink/White)

Silicon Dioxide (SiO2) - Variety of Chalcedony

Amethyst (Purple), Sulfur (Yellow), and Blue Apatite (SiO2 (Quartz), S (Native Sulfur), Ca5(PO4)3(F,Cl,OH) (Apatite Group)) — mineral

Amethyst (Purple), Sulfur (Yellow), and Blue Apatite

SiO2 (Quartz), S (Native Sulfur), Ca5(PO4)3(F,Cl,OH) (Apatite Group)

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

Hematite

Iron(III) oxide (Fe2O3)

Green Fluorite (Calcium Fluoride (CaF2)) — mineral

Green Fluorite

Calcium Fluoride (CaF2)

Peridot (Olivine (Magnesium Iron Silicate), (Mg, Fe)2SiO4) — mineral

Peridot

Olivine (Magnesium Iron Silicate), (Mg, Fe)2SiO4

Amethyst (Amethyst (Silicon Dioxide containing trace Iron impurities, SiO2)) — mineral

Amethyst

Amethyst (Silicon Dioxide containing trace Iron impurities, SiO2)

Amethyst (Tumbled) (Amethyst (Silicon Dioxide with Iron impurities) - SiO2) — mineral

Amethyst (Tumbled)

Amethyst (Silicon Dioxide with Iron impurities) - SiO2