Obsidian
Volcanic Glass (70% or more SiO2)
Category
Browse organic (non geological) specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (70% or more SiO2)
Amber
Succinite (formula varies, primarily C10H16O)
Polymer Clay (Mock Mineral)
Polyvinyl chloride (PVC) with plasticizers and pigment
Black Obsidian
Volcanic Glass (70–75% SiO2 plus MgO, Fe3O4)
Petrified Wood
Silicified Wood (SiO2)
Black Obsidian
Obsidian (Amorphous volcanic glass, SiO2)
Obsidian
Volcanic Glass (predominantly SiO2)
Shale or Argillite
Shale (fine-grained clastic sedimentary rock) or Argillite (low-grade metamorphic rock derived from shale)
Slag Glass
Vitreous Silicate Residue
Slag
Glassy silicate byproduct (anthropogenic material)
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide , SiO2)
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
Fossiliferous Limestone
CaCO3 (principally Calcite or Aragonite)
Chert (Yellow Jasper variant)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Coral Fossil (Scleractinia)
Scleractinia (Order), primarily CaCO3 (Aragonite or Calcite)
Chert (specifically Jasper/Flint)
Microcrystalline Quartz (SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Slag Glass (Cullet)
Amorphous Silicon Dioxide (SiO2) with metal oxide colorants
Chert (Limestone-based)
Silicon dioxide (SiO2)
Chrysanthemum Stone
Celestine (SrSO4) or Calcite (CaCO3) in Limestone/Porphyry matrix
Chert (Nodule)
Silicon Dioxide (SiO2)
Chert (variant Flint or Jasper)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Jasper variety)
Cryptocrystalline Quartz (SiO2)
Chert / Jasper
Microcrystalline Quartz (SiO2)
Chert (with Limestone matrix)
Microcrystalline Quartz (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Quartzite
Quartzite (primarily SiO2)
Obsidian
Amorphous volcanic glass (primarily SiO2)
Obsidian
Obsidian (Volcanic Glass)
Snowflake Obsidian
Volcanic glass (SiO2) with Cristobalite (SiO2) inclusions
Slag (Industrial Glass)
Artificial Vitreous Silicate
Black Obsidian
Volcanic Glass (SiO2 + impurities)
Banded Sandstone (Liesegang Rings)
Sedimentary sandstone with Iron oxide precipitates
Slag (Industrial Byproduct)
Ferrous/Non-ferrous Silicate
Snowflake Obsidian
Vitreous Volcanic Rock (Amorphous Silicate), SiO2
Obsidian
Volcanic Glass (SiO2 + impurities)
Glass Nugget (Tumbled Glass)
Amorphous Silicon Dioxide (SiO2) with additives
Obsidian
Volcanic Glass (SiO2 dominant)
Obsidian
Volcanic glass (SiO2 - Silicon dioxide predominant composition)
Drill Core Sample
Cylindrical Rock Core (Specific mineralogy varies by extraction site)
Granite
Granite (Felsic Plutonic Rock)