Thunderegg (Agate-filled Geode Node)
Silicon dioxide (SiO2) with various inclusions
Category
Browse the purple specimen is a mineral (amethyst); the white specimen is a sedimentary rock (limestone or marble). specimens identified by the Rock Identifier community.
Thunderegg (Agate-filled Geode Node)
Silicon dioxide (SiO2) with various inclusions
Sandstone
Clastic Sedimentary Rock (composed mostly of quartz, SiO2)
Connemara Marble
Ophiocalcite (Serpentinitic Marble)
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Chert Conglomerate (or Breccia)
Sedimentary Clastic Rock (variety: Ferruginous Chert Breccia)
Quartzite
Quartzite (primarily SiO2)
Chert (Jasper-like)
SiO2 (Cryptocrystalline Quartz)
Agate Geode
Chalcedony (cryptocrystalline SiO2)
Sandstone Pebble with Iron Staining
Clastic Sedimentary Rock (primarily Quartz with Fe2O3 oxides)
Granite (Leucogranite)
Felsic Plutonic Rock (Granite)
Lapis Lazuli
Lapis Lazuli (Complex silicate: Na8[Al6Si6O24]Sn)
Quartz in Matrix (possibly with Biotite or Hornblende)
Quartz (Silicon Dioxide, SiO2) in Granitic Matrix
Banded Agate
Silicon Dioxide (SiO2) - Chalcedony variety
Chert (Jasper variety)
Silicon Dioxide (SiO2)
Quartz Crystal (specifically a small Clear Quartz point)
Silicon Dioxide (SiO2)
Gneiss (River Cobble)
Gneiss (Foliated Metamorphic Rock)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz (Milky Quartz/Citrine Type)
Silicon Dioxide (SiO2)
Chalcopyrite
Chalcopyrite (CuFeS2)
Jasper with Quartz inclusions
Silicon Dioxide (SiO2) - Microcrystalline Chalcedony
Chert (Flint)
Chert (SiO2)
Chert / Flint
Microcrystalline Quartz (SiO2)
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
Yellow Quartz (Chalcedony/Citrine Pebble)
Silicon Dioxide (SiO2)
Quartz Geode
Silicon Dioxide (SiO2)
Quartz Crystal Fragment
Silicon Dioxide (SiO2)
Chert (and Fossilized Brachiopod shell)
Sedimentary Cryptocrystalline Quartz (SiO2)
Grey River Stone (Quartz-rich Quartzite/Siltstone)
Quartzite / Meta-siltstone (primarily SiO2)
Fossiliferous Limestone with Rugose Coral
Calcite (CaCO3) containing a Rugosa (Horn Coral) fossil
Quartz pebble with surface markings
Silicon Dioxide (SiO2)
Ruby
Corundum (mineral species), variety: Ruby (Al2O3 with Cr3+ as the chromophore)
Amethyst
Silicon Dioxide (SiO2) with Iron impurities
Chert (Chert Nodule with Cortex)
Microcrystalline Quartz (SiO2)
Orange Calcite
Calcium Carbonate (CaCO3)
Shale (sub-type: Carbonaceous Shale)
Lutaceous Sedimentary Rock
Veined Limestone (Micrite) with Quartz/Calcite Veins
Calcium Carbonate (CaCO3) with Silicate or Carbonate inclusions
Limonite and Goethite encrusted Chert/Ironstone
Hydrated Iron Oxide (FeO(OH)·nH2O) with cryptocrystalline Silica (SiO2)
Fossilized Solitary Rugose Coral (Horn Coral)
Order: Rugosa (e.g., Grewingkia or Heliophyllum); composed of Calcite (CaCO3) or Silica (SiO2)
Specular Hematite with Quartz and Limonite
Hematite (Fe2O3) with Quartz (SiO2) and Limonite (FeO(OH)·nH2O)
Bivalve Fossil (Internal Mold)
Class Bivalvia (Phylum Mollusca)
Red Jasper with Quartz Veining
Silicon Dioxide (SiO2) - Microcrystalline Quartz with Iron Oxide impurities (Hematite)