Chert (River Pebble)
Microcrystalline Quartz (SiO2)
Category
Browse organic structure (not a rock) specimens identified by the Rock Identifier community.
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
Concretion
Septarian or Siderite Concretion
Petrified Wood
Silicified Wood (SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Chalcedony
Cryptocrystalline Quartz (SiO2)
Shungite
Non-crystalline carbon (similar to anthracite coal or meta-anthracite)
Chert (White-Tan variety)
Silicon dioxide (SiO2) / Microcrystalline Quartz
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
Quartz Geode
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Chert (specifically Flint or Jasper variant)
Microcrystalline Quartz (SiO2)
Fossiliferous Limestone
Biogenic Sedimentary Rock (Calcite, CaCO3)
Fossilized bone fragment
Fossil bone, composed chiefly of carbonate-fluorapatite (bioapatite)
Coral Rock (Coquina)
Biogenic Limestone (Calcium Carbonate - CaCO3)
Chert / Flint
Chert (Silicon Dioxide, SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Silty Shale or Mudstone
Siltstone/Mudstone (Clastic Sedimentary Rock)
Weathered fossil fragment, possibly bone
Indeterminate fossilized bone; likely mineralized vertebrate bone (apatite-rich)
Fossilized Coral
Cnidaria (Anthozoa), often replaced by Calcium Carbonate (CaCO3) or Silica (SiO2)
Chrysanthemum Stone
Celestite or Calcite crystal aggregates in limestone
Shale
Shale (Sedimentary rock composed of mud/clay minerals)
Lapis Lazuli
Na8[Al6Si6O24]S2 (Lazurite component), a rock composed primarily of Lazurite, Calcite, and Pyrite
Chert (Jasper/Agate)
Silicon Dioxide (SiO2)
Chert (Flint)
Chert (Cryptocrystalline Silicon Dioxide, SiO2)
Fossilized bone fragment (probable mammalian tooth or bone)
Mineralized bone, commonly hydroxyapatite [Ca5(PO4)3(OH)] replaced or impregnated by silica/calcite
Amber
Fossilized Tree Resin
Chert (Flint Nodules)
Silicon Dioxide (SiO2)
Limestone with Lichen
Carbonate Sedimentary Rock (primarily CaCO3)
Chert (Flint)
Silicon Dioxide (SiO2)
Chert (Gravel)
Chert (Microcrystalline Silicon Dioxide, SiO2)
Chert
Chert (SiO2)
Chert (Jasper-like Silicate)
Microcrystalline Quartz (SiO2)
Chert / Jasper / Agate (Chalcedony Group)
Microcrystalline Quartz (SiO2)
Chert Concretion (Flint)
Silicon Dioxide (SiO2)
Chert (Quartz Variety)
Chert (Silicon Dioxide, SiO2)
Chert (Brown Variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with Bioclastic Inclusions
Graphite-rich metamorphic rock (graphitic schist)
Graphitic schist; chiefly graphite (C), quartz (SiO₂), and mica minerals
Fossiliferous Limestone
Sedimentary rock containing Indeterminate Fossil remains (likely Crinoid stem or Bryozoan fragment)
Ironstone Concretion (Limonite/Goethite)
Goethite/Limonite concretion (FeO(OH)·nH2O)
Fossilized Shell Fragment
Invertebrate fossil / Brachiopod or Mollusk shell fragment (Calcium carbonate, CaCO3)
Fossilized Coral (Petoskey Stone or Rugose Coral)
Antophyllum (Hexagonaria) or Scleractinia (CaCO3)