Quartz (Iron-stained)
Silicon Dioxide (SiO2)
Category
Browse industrial byproduct (often mistaken for obsidian or mineral) specimens identified by the Rock Identifier community.
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
Dendritic Opal (Merlinite)
Hydrated Silica with Manganese/Iron oxide inclusions (SiO2·nH2O)
Chrysoprase
Silicon dioxide (SiO2) with nickel impurities
Black Spinel
Magnesium Aluminum Oxide (MgAl2O4)
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
Concretion
Septarian concretion (likely containing Calcite or Siderite)
Obsidian
Volcanic Glass (SiO2)
Obsidian
Volcanic Glass (predominantly SiO2, approximately 70% or more)
Dumortierite Quartz
Al7BO3(SiO4)3O3 (Borosilicate mineral/Quartz inclusion)
Sodalite
Na8(Al6Si6O24)Cl2
Sandstone Concretion
Clastic Sedimentary Concretion (typically Quartz/Silica with Iron Oxide)
Satin Spar Selenite
Satin Spar (Calcium Sulfate Dihydrate, CaSO4·2H2O)
Obsidian
Obsidian (Volcanic Glass)
Sandstone with Dendritic Manganese Oxides
Sandstone (SiO2 predominant) with Oxide Dendrites (MnO2)
Green Aventurine
Aventurine Quartz (SiO2 with inclusions of Fuchsite mica)
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
Sodalite
Na8(Al6Si6O24)Cl2
Auriferous Quartz or Pyritic Ore
Iron Pyrite (FeS2) or Native Gold (Au) in Matrix
Obsidian
Obsidian (Volcanic Glass)
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
Obsidian
Volcanic Glass (felsic composition)
Obsidian
Volcanic Glass (Silicon Dioxide with impurities)
Blue Dumortierite in Quartz
Al7(BO3)(SiO4)3O3 (Dumortierite)
Obsidian
Obsidian (Volcanic Glass)
Citrine (Yellow Quartz)
Silicon Dioxide (SiO2)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Cannonball Concretion
Calcite-cemented Sandstone Concretion
Mahogany Obsidian
Volcanic glass (SiO2 with Hematite or Magnetite inclusions)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Banded Sandstone Peabble
Arenite with iron oxide banding
Blue Apatite
Fluorapatite / Chlorapatite [Ca5(PO4)3(F,Cl,OH)]
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Obsidian
Volcanic Glass (SiO2)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Ferruginous Quartz (Iron-stained Quartz)
Quartz with Iron Oxide inclusions (SiO2 with Fe2O3)
Goethite Concretion
Goethite (FeO(OH))
Ferruginous Sandstone (Ironstone Conglomerate fragments)
Ferruginous clastic sedimentary rock (SiO2 cemented by Fe2O3)
Obsidian
Volcanic glass (silica-rich rhyolitic melt; primarily SiO₂)
Obsidian
Volcanic Glass (comprised primarily of SiO2)
Mahogany Obsidian
Volcanic Glass (predominantly SiO2 with inclusions of Hematite or Magnetite)
Dalmation Jasper
Perthitic Feldspar with Arfvedsonite inclusions