Basalt
Basalt
Igneous
Category
Industrial Byproduct (Often Mistaken For Obsidian Or Mineral)
Browse industrial byproduct (often mistaken for obsidian or mineral) specimens identified by the Rock Identifier community.
Ironstone Concretion (Limonite/Goethite)
Iron oxide concretion (contains FeO(OH)·nH2O)
sedimentary
Obsidian
Obsidian (Amorphous volcanic glass, SiO2 rich)
igneous
Blue Quartzite
Blue Quartzite (Primary mineral: Quartz, SiO2 with magnesio-riebeckite or crocidolite inclusions)
metamorphic
Obsidian
Volcanic glass (mainly SiO2 with inclusions)
igneous
Sodalite
Sodalite - Na8(Al6Si6O24)Cl2
mineral
Chrysoprase
Silicon Dioxide (Nickel-bearing Chalcedony) - SiO2
mineral
Blue Apatite
Apatite group (Ca5(PO4)3(F,Cl,OH))
mineral
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Ferruginous Quartz
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
mineral
Green Aventurine (Green Quartzite)
Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2(AlSi3O10)(OH)2)
metamorphic
Jasper with Manganese Dendrites
Silicon Dioxide (SiO2) with Oxide Mineral Inclusions
sedimentary
Ironstone concretion / Limonitic Sandstone
Goethite/Hematite Cemented Sandstone (Hydrated Iron Oxide)
sedimentary
Snowflake Obsidian
Volcanic glass containing Spherulites (SiO2)
igneous
Pyrite
Iron Sulfide (FeS2)
mineral
Black Obsidian and Hematite
Volcanic Glass (SiO2) and Hematite (Fe2O3)
igneous and mineral
Black Star Diopside (beads)
Diopside (CaMgSi2O6) - a member of the pyroxene group
Mineral
Liesegang Banded Sandstone (Wonderstone)
Ferruginous Sandstone with Liesegang Rings
sedimentary
Pyrite in Shale
Iron Sulfide (FeS2)
mineral
Bismuth Crystal
Bismuth (Bi)
mineral
Scoria (with likely iron oxidation)
Scoria (Basaltic Scoria)
igneous
Black Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Iron-stained Quartz
Silicon Dioxide (SiO2) with Limonite/Hematite inclusions
mineral
Sodalite
Na8(Al6Si6O24)Cl2
mineral
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
mineral
Epidote (or Epidote-rich rock)
Epidote. Mineral formula: Ca2(Al,Fe)3(SiO4)3(OH).
Mineral, often found in metamorphic rocks but also in sedimentary and igneous rocks
Sodalite in Matrix (often called Blue Marble or Sodalite-Syenite)
Sodalite-bearing Syenite / Na8Al6Si6O24Cl2 (Sodalite component)
igneous
Ironstone Concretion (Limonite/Goethite)
Goethite-rich Concretion (FeO(OH))
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Snowflake Obsidian
Spherulitic Volcanic Glass (SiO2 + impurities)
igneous
Green Aventurine
Silicon Dioxide (SiO2) with Fuchsite inclusions
metamorphic
Scoria (Lava Rock)
Mafic extrusive volcanic rock (Scientific formula varies based on mineral content: primarily SiO2, MgO, and FeO)
igneous
Snowflake Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with Cristobalite inclusions)
igneous
Ferruginous Quartz (Iron-stained Quartz)
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
mineral
Blue Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
mineral
Ironstone Concretion (Limonite/Hematite Nodules)
Ironstone (principally Limonite FeO(OH)·nH2O or Hematite Fe2O3 mixed with silica/clay)
sedimentary
Sandstone with Ironstone Concretion
Arenite with Hematite/Goethite nodules (Fe2O3 / FeO(OH))
sedimentary
Greenstone
Greenschist (primarily composed of chlorite, actinolite, and epidote)
metamorphic
Dioptase
Dioptase (CuSiO3 · H2O)
mineral
Scoria (Lava Rock)
Scoria
igneous
Banded Sandstone
Arenite with Liesegang banding
sedimentary
Muscovite Schist
Muscovite Mica Schist (KAl2(AlSi3O10)(OH)2)
metamorphic