Quartzite
Quartzite (primarily SiO2)
Category
Browse organic (non geological) specimens identified by the Rock Identifier community.
Quartzite
Quartzite (primarily SiO2)
Obsidian
Obsidian (Volcanic Glass, primarily SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Petrified Wood
Silicified Wood (primarily SiO₂ / Silicon Dioxide)
Obsidian
Obsidian (Volcanic Glass)
Petrified Wood (Silicified Wood)
Silicified Wood / Silicon Dioxide (SiO2)
Biological Bone (Patella/Knee)
Patella (part of the Human Skeletal System)
Obsidian
Volcanic Glass (SiO2, usually >70% silica content)
Chert / River Jasper
Microcrystalline Quartz (SiO2)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide)
Obsidian
Obsidian (principally SiO2 - Silicon Dioxide)
Coal (most likely Bituminous or Anthracite)
Coal (organic sedimentary rock)
Magnetic Hematite
Magnetized Hematite (an iron oxide mineral, Fe2O3, that has undergone magnetization)
Fossiliferous Limestone with Rugose Coral
Calcium Carbonate (CaCO3) featuring Rugosa (extinct order of solitary and colony corals)
Petrified Wood
Silicified Wood (SiO2)
Obsidian
Volcanic Glass (predominantly SiO2)
Chert (with Quartz Veining)
Chert (formula: SiO2)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Obsidian
Volcanic Glass (SiO2 rich)
Green Moss Agate
Agate (Silicon Dioxide - SiO2) with inclusions of hornblende or chlorite
Obsidian
Volcanic glass (no mineral formula due to amorphous structure, mostly SiO2)
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
Mahogany Obsidian
Obsidian (Volcanic Glass) with Hematite/Magnetite inclusions
Petrified Wood (Silicified Wood)
Silicified Wood (primarily Chalcedony/Quartz, SiO2)
Petrified Wood
Silicified Wood (SiO2)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (70% or more silicon dioxide)
Petrified Wood (Agatized/Silicified Wood)
Silicified Wood (SiO2)
Chalk
Calcium Carbonate (CaCO3)
Limestone (Concretionary or Tufa)
Calcium Carbonate (CaCO3)
Chert (White/Light Tan)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Nodular)
Chert (SiO2 - Microcrystalline Quartz)
Chert Pebble with Quartz Veins
Microcrystalline Quartz (SiO2)
Chert (specifically Tan/Brown Chert)
Chert (SiO2)
Chert (Cherty Shale / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Quartz Vein in Schist
Quartz (SiO2) in Mica Schist
Shale
Shale (fine-grained clastic sedimentary rock)
Obsidian
Volcanic Glass (predominantly SiO2, approximately 70% or more)
Sandstone
Sandstone (clastic sedimentary rock, composed predominantly of sand-sized minerals or rock fragments)
Obsidian
Obsidian (volcanic glass), primarily SiO2 (silicon dioxide)
Petrified Wood
Silicified Wood (SiO2)