Carborundum (Silicon Carbide)
Silicon Carbide (SiC)
Category
Browse industrial byproduct (often mistaken for obsidian or mineral) specimens identified by the Rock Identifier community.
Carborundum (Silicon Carbide)
Silicon Carbide (SiC)
Quartzite
Quartzite (primarily SiO2)
Obsidian
Volcanic glass
Bismuth
Bismuth (element Bi) with oxidized thin-film interference layer
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)
Dalmatian Jasper
Peralkaline rhyolite with Arfvedsonite inclusions
Sandstone Concretion
Sedimentary concretion
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Jasper (Multi-colored) / Sea Glass Slag
Silicon Dioxide (SiO2) with impurities of Iron Oxide
Mother of Pearl (Nacre)
Aragonite (CaCO3) with Organic Matrix
Mahogany Obsidian
Obsidian (volcanic glass with hematite/magnetite inclusions)
Obsidian
Volcanic Glass (Amorphous SiO2)
Obsidian
Obsidian (principally SiO2)
Black Obsidian
Volcanic Glass (SiO2)
Amazonite
KAlSi3O8 (Potassium Aluminum Silicate) - a variety of Microcline Feldspar
Siltstone with iron staining
Siltstone (primarily SiO2 with FeO(OH) coatings)
Obsidian (Gold Sheen)
Obsidian (SiO2 + impurities)
Sulfur (with possible Cullet Glass or Slag imitation)
Native Sulfur (S8)
Quartzite
Quartzite (SiO2)
Black Obsidian
Obsidian, SiO2 (amorphous)
Obsidian
Volcanic Glass (Amorphous Silica)
Obsidian
Volcanic glass (high silica SiO2)
Quartz Pebble (with Manganese dendrites/staining)
Silicon Dioxide (SiO2) with Manganese Oxide impurities
Obsidian
Volcanic Glass (predominantly SiO2)
Obsidian (likely Golden Sheen Obsidian or Rainbow Obsidian, given the subtle sheen visible on some beads)
Obsidian (volcanic glass, predominantly SiO2 with various impurities)
Mahogany Obsidian
Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)
Yellow Jasper with Dendritic Inclusions
Silicon Dioxide (SiO2) with Manganese/Iron Oxide inclusions
Manganese-coated Sandstone
Clastic sedimentary rock with Manganese Oxide (often Pyrolusite or Psilomelane)
Yellow Aventurine
Quartzite with inclusions (SiO2)
Green Aventurine
Silicon Dioxide (SiO2) with Fuchsite inclusions
Black Spinel
Magnesium Aluminum Oxide (MgAl2O4)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Obsidian
Amorphous volcanic glass (primarily SiO2)
Smoky Quartz
Quartz (SiO₂)
Sandstone (Ferruginous Concretion)
Ferruginous Sandstone Concretion / SiO2 with Fe2O3 cement
Mahogany Obsidian
Volcanic Glass with Hematite inclusions (SiO2 + Fe2O3)
Silver (Jewelry form)
Native Silver (Ag)
Obsidian
Obsidian (Volcanic Glass)
Aura Quartz (Titanium Quartz)
Titanium-coated Silicon Dioxide (SiO2 + Ti)
Siltstone/Sandstone (possibly Wonderstone or Picture Sandstone)
Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide inclusions)
Obsidian
Obsidian (Volcanic Glass)
Asphalt (Aggregate)
Bituminous macadam / Concrete Aggregate