Obsidian
Volcanic Glass (predominantly SiO2)
Category
Browse non geological specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (predominantly SiO2)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Obsidian
Volcanic Glass (SiO2, usually >70% silica content)
Sandstone
Sandstone (clastic sedimentary rock, composed predominantly of sand-sized minerals or rock fragments)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Obsidian
Obsidian (Volcanic Glass, primarily SiO2)
Obsidian
Volcanic Glass (predominantly SiO2, approximately 70% or more)
Gold Ore
Native Gold (Au) in Matrix
Man-made Synthetic Material (Plastic/Composite)
Acrylonitrile Butadiene Styrene (ABS) or High-Impact Polystyrene (HIPS)
Chert (River Pebble)
Chert (Cryptocrystalline Quartz, SiO₂)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide)
Obsidian
Volcanic glass (no mineral formula due to amorphous structure, mostly SiO2)
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
Obsidian
Obsidian (volcanic glass), primarily SiO2 (silicon dioxide)
Quartzite
Quartzite (Metamorphic Quartz Arenite)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (70% or more silicon dioxide)
Opalite (a synthetic glass)
Silicon Dioxide (SiO2) with various additives; not a true mineral but a man-made gem simulant
Mahogany Obsidian
Obsidian (Volcanic Glass) with Hematite/Magnetite inclusions
Peridot
Olivine ((Mg,Fe)2SiO4)
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Obsidian
Obsidian (principally SiO2)
Obsidian
Volcanic glass (high silica content, usually >70% SiO2)
Quartzite
Metamorphic Quartzite (primarily SiO2)
Fossils in Limestone (Crinoid / Marine Invertebrate Fossil)
Fossiliferous Limestone (containing Crinoidea / Brachiopoda)
Apache Tear
Obsidian (Hydrated Volcanic Glass - SiO2)
Obsidian
Obsidian (Volcanic glass, primarily SiO2)
Note: Item is a Synthetic/Man-made Object
Titanium-coated Stainless Steel (Fe-Cr-Ni-Ti)
Milky Quartz
Silicon Dioxide (SiO2)
Mahogany Obsidian
Obsidian (Volcanic Glass) with Hematite or Magnetite inclusions, SiO2 (Silicon Dioxide)
Tumbled Obsidian (possibly Mahogany Obsidian variant)
Volcanic Glass (Amorphous Silicon Dioxide, SiO2)
Likely obsidian (possibly tektite or slag glass)
Volcanic glass; primarily SiO₂, noncrystalline
Slag Glass (Cullet)
Amorphous Silica / Glass residue
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (mostly SiO2)
Engineered Quartz
Silicon dioxide composite
Black Obsidian
Volcanic Glass (predominantly SiO2, Silicon Dioxide)
Obsidian
Volcanic glass (Mainly SiO2)
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)
Quartz with Iron Oxide Staining
Silicon Dioxide (SiO2)
Quartz (likely) or a Quartzite Pebble
Silicon dioxide (SiO2) for quartz. If it's quartzite, it's a metamorphic rock primarily composed of quartz.
Fossil Coral (Petoskey / Horn Coral Sliced Button)
Scleractinia / Rugosa (Silurian-Devonian Anthozoa)
Quartzite
Metamorphic Quartzite (SiO2)