Green Aventurine
Silicon Dioxide (SiO2) with Fuchsite inclusions
metamorphic
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.
Learn about Industrial Byproduct (Often Mistaken For Obsidian Or Mineral) in the encyclopedia
View all →
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (mostly SiO2)
igneous
Mahogany Obsidian
Volcanic Glass (SiO2 + Fe2O3)
igneous
Obsidian
Volcanic glass (SiO2 - Silicon dioxide predominant composition)
Igneous
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions (SiO2)
igneous
Obsidian
Obsidian (principally SiO2 - Silicon Dioxide)
igneous
Snowflake Obsidian
Volcanic Glass with Cristobalite inclusions
igneous
Black Spinel
Magnesium Aluminum Oxide (MgAl2O4)
mineral
Black Onyx
Silicon Dioxide (SiO2) with parallel banding
mineral
Black Obsidian
Amorphous volcanic glass (SiO2)
igneous
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Sandstone (Ferruginous Concretion)
Ferruginous Sandstone Concretion / SiO2 with Fe2O3 cement
sedimentary
Obsidian
Volcanic Glass (Amorphous SiO2-rich glass)
Igneous
Ironstone Concretion (Limonite/Goethite)
Iron-rich sedimentary rock (FeOx)
sedimentary
Obsidian
Obsidian (Volcanic Glass)
igneous
Mahogany Obsidian
Obsidian (Volcanic Glass) with Hematite or Magnetite inclusions, SiO2 (Silicon Dioxide)
igneous
Black Obsidian
Volcanic Glass (Silicon Dioxide with impurities)
igneous
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Igneous
Snowflake Obsidian (Tumbled)
Obsidian with Cristobalite inclusions
igneous
Sandstone Concretion
Limonitic Sandstone Concretion
sedimentary
Aura Quartz (Titanium Quartz)
Titanium-coated Silicon Dioxide (SiO2 + Ti)
mineral
Siltstone/Sandstone (possibly Wonderstone or Picture Sandstone)
Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide inclusions)
Sedimentary
Tiffany Stone
Bertrandite-Bearing Fluorite Hyalite Opal
metamorphic
Obsidian
Extrusive igneous volcanic glass (rich in SiO2)
igneous
Milky Quartz or Calcite Pebble
Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3)
mineral
Chert Concretion (Flint)
Silicon Dioxide (SiO2)
sedimentary
Obsidian
Obsidian (Volcanic Glass, SiO2)
igneous
Obsidian
Obsidian (Volcanic Glass)
igneous
Claystone Concretion
Septarian Concretion (Ironstone-rich)
sedimentary
Sandstone Concretion
Sedimentary Concretion (SiO2 or CaCO3 cemented)
sedimentary
Dendritic Agate (Tumbled)
Silicon Dioxide (SiO2) with inclusions
mineral
Ironstone (likely Limonite or Goethite nodule)
Hydrothermally altered Ferric Hydroxide (FeO(OH)·nH2O)
sedimentary
Sandstone Concretion
Ferruginous Sandstone Concretion
sedimentary
Green Rutilated Quartz
Silicon Dioxide with Actinolite inclusions (SiO2 + Ca2(Mg,Fe)5Si8O22(OH)2)
mineral
Snowflake Obsidian
Spherulitic Obsidian (Volcanic Glass with Cristobalite inclusions)
igneous
Obsidian
Volcanic Glass (SiO2 - Silicon Dioxide with impurities)
Igneous
Black Obsidian
Obsidian (Volcanic Glass)
igneous
Mahogany Obsidian
Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)
igneous
Obsidian
Volcanic Glass (mostly SiO2)
igneous
Obsidian
Volcanic Glass (SiO2)
igneous
Chrysocolla in Quartz (Gem Silica)
Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O (Chrysocolla) / SiO2 (Quartz)
mineral
Sandstone Concretion
Ferruginous Sandstone Concretion (SiO2 + FeO(OH))
sedimentary