Quartzite
Quartzite (composed primarily of Quartz, SiO2)
Category
Browse industrial byproduct (often mistaken for obsidian or mineral) specimens identified by the Rock Identifier community.
Quartzite
Quartzite (composed primarily of Quartz, SiO2)
Goldstone (Brown)
Aventurine Glass (Silicon Dioxide infused with Copper crystals)
Bryozoan Fossil
Phylum Bryozoa (commonly known as 'moss animals')
Banded Slate (Lithified Mudstone)
Low-grade Metamorphosed Mudstone / Slate
Black Spinel
Magnesium Aluminum Oxide (MgAl2O4)
Snowflake Obsidian
Volcanic Glass (spherulitic Obsidian) - SiO2 (with Cristobalite inclusions)
Gold Sheen Obsidian
Volcanic Glass (SiO2 + H2O + Fe2O3)
Diamond (or Cubic Zirconia)
Carbon (C) or Zirconium Dioxide (ZrO2)
Snowflake Obsidian
Obsidian with Cristobalite inclusions (SiO2)
Sodalite
Sodalite, Na8(Al6Si6O24)Cl2
Ironstone Concretion
Siderite or Hematite Concretion (FeCO3 or Fe2O3)
Chert (Nodule)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Obsidian (specifically Silver Sheen Obsidian)
Volcanic Glass (approx. 70–75% SiO2 plus MgO, Fe3O4)
Pyrite in Matrix (Commonly called Fool's Gold)
Iron Sulfide (FeS2)
Quartzite
Quartzite (primarily SiO2)
Chert (Iron-Stained)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Opalite
Man-made Glass (SiO2 + additives)
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)
Snowflake Obsidian
Volcanic Glass with Cristobalite inclusions (70–75% SiO2)
Black Sapphire (Basaltic Blue Sapphire)
Corundum (Al2O3)
Mahogany Obsidian
Volcanic Glass with Hematite (SiO2 + Fe2O3)
Opalite
Man-made Synthetic Glass (Silicon Dioxide with metal additives)
Scoria
Vesicular Basalt / Scoria
Quartzite
Quartzite (primarily SiO2)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Quartzite
Quartzite (primarily SiO2)
Siltstone
Siltstone (primarily SiO2 with Al2O3)
Ferruginous Sandstone with Ironstone Concretion
Goethite-rich Sandstone (FeO(OH))
Diorite
Diorite
Black Obsidian
Volcanic Glass (Amorphous Silicon Dioxide SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Garnet-bearing Schist
Almandine Garnet [Fe3Al2(SiO4)3] in Micaceous Schist
Tektite (Indochinite)
Tektite (High-silica natural glass)
Snowflake Obsidian
Vitreous volcanic silicate rock (SiO2) with Spherulite inclusions
Silicon
Element Si
Ferruginous Sandstone (Ironstone)
Sedimentary rock with high iron oxide content (Fe2O3 / FeO(OH))
Apache Tear
Hydrated Obsidian (Volcanic Glass)
Bicolor Quartz (Milk Quartz with Slag or Dark Inclusions)
Silicon Dioxide (SiO2) with impurities
Snowflake Obsidian
Volcanic Glass with Spherulite Inclusions (70–75% SiO2)
Apache Tear
Obsidian (Hydrated Silica Glass)
Quartz (Iron-Stained)
Crystalline Silicon Dioxide (SiO2)
Limonite (Ironstone Concretion)
Limonite (Hydrous ferric oxide mixture, FeO(OH)·nH2O)