Black obsidian
Volcanic glass; predominantly rhyolitic silica-rich melt (approximately 70–80% SiO₂), lacking crystalline structure
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.
Learn about Industrial Byproduct (Often Mistaken For Obsidian Or Mineral) in the encyclopedia
View all →
Black Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Aventurine
Silicon dioxide (Quartz) with inclusions (KAl2(AlSi3O10)(OH)2)
mineral
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide)
Igneous
Obsidian (Black Obsidian)
Obsidian (Volcanic Glass)
igneous
Quartzite
Quartzite (composed primarily of SiO2)
metamorphic
Quartzite
Quartzite (SiO2)
metamorphic
Ironstone Concretion / Hematite Nodules
Ferruginous Sedimentary Rock (primarily Hematite Fe2O3 and Goethite FeO(OH))
sedimentary
Quartzite Pebble
Quartzite (SiO2 with minor impurities)
metamorphic
Obsidian
Obsidian (Volcanic Glass, SiO2)
igneous
Silver (Native Element)
Ag (Argentum)
mineral
Bismuth
Bismuth (element Bi) with oxidized thin-film interference layer
mineral
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
igneous
Obsidian
Obsidian (Amorphous volcanic glass)
igneous
Obsidian
Volcanic glass
igneous
Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
igneous
Polished mahogany obsidian
Volcanic glass (mostly SiO₂), commonly called mahogany obsidian
igneous
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (70–75% SiO2)
Igneous
Mica-rich Sandstone or Micaceous Schist Weathering
Micaceous Schist (Muscovite-Quartz composition)
Metamorphic or Sedimentary depending on local grade
Carborundum
Silicon Carbide (SiC)
mineral
Dendritic Siltstone
Siltstone with Manganese Oxide dendrites (MnO2)
sedimentary
Green Quartz (Prasiolite or Aventurine)
Silicon Dioxide (SiO2)
mineral
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
mineral
Green Quartz (Aventurine)
Silicon Dioxide (SiO2) with inclusions of Fuchsite
mineral
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
mineral
Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
igneous
Mother of Pearl (Nacre)
Aragonite (CaCO3) with Organic Matrix
mineral
Unidentified dark pebble
Undetermined; possibly polished basalt, chert, or iron-rich stone
mineral
Snowflake Obsidian and Green Aventurine
Volcanic Glass (SiO2 with Cristobalite inclusions) and Quartz (SiO2 with Fuchsite)
igneous and metamorphic
Obsidian
Volcanic Glass (Amorphous SiO2)
igneous
Quartzite
Quartzite (primarily SiO2)
metamorphic
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite (SiO2 + Fe2O3)
igneous
Ironstone Concretion
Ironstone (Limonite/Goethite/Hematite mixture)
sedimentary
Mica Schist with Pyrite
Muscovite/Biotite Schist with Iron Sulfide (FeS2)
metamorphic
Aura Quartz (Pink/Rose Aura Quartz)
Silicon Dioxide (SiO2) bonded with Platinum and/or Silver
mineral
Snowflake Obsidian
Obsidian with Cristobalite inclusions
igneous
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
igneous
Chert (often called Flint in archaeological contexts)
Microcrystalline or cryptocrystalline Silica (SiO2)
sedimentary
Carborundum (Silicon Carbide)
Silicon Carbide (SiC)
mineral (synthetic)
Tiger's Eye, Hematite, and Black Obsidian Bracelet
SiO2 (Tiger's Eye), Fe2O3 (Hematite), and 70-75% SiO2 (Obsidian)
mineral