Geode (Unopened)
Silica-rich concretion (SiO2)
Category
Browse organic materia (not a rock or mineral) specimens identified by the Rock Identifier community.
Geode (Unopened)
Silica-rich concretion (SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Chert (Holey Stone)
Microcrystalline Quartz (SiO2)
Septarian Nodule (Dragon Stone)
Septarian concretion (composition: CaCO3 - Calcite, Aragonite, and Siderite/Limestone)
Chert (White-Tan variety)
Silicon dioxide (SiO2) / Microcrystalline Quartz
Chert (Nodule)
Microcrystalline or Cryptocrystalline Silica (SiO2)
Amber
Succinite (with formula approximately C10H16O)
Pink Opal (Common Opal)
Amorphous Hydrated Silica (SiO2·nH2O)
Sandstone Concretion
Clastic sedimentary rock (primarily Quartz SiO2)
Quartz Geode
Silicon Dioxide (SiO2)
Coal (most likely Bituminous or Anthracite)
Coal (organic sedimentary rock)
Pyrite Geode (Sparkling Druzy)
Iron Sulfide (FeS2) in Sedimentary Nodule
Travertine
Calcareous Tufa / Travertine (CaCO3)
Petrified Wood
Silicified Wood (primarily SiO2)
Amber
Succinite (formula varies, primarily C10H16O)
Chert (Jasper variation)
Microcrystalline Quartz (SiO2)
Coal (likely Bituminous or Lignite)
Organic Sedimentary Rock (Carbonaceous)
Chert / Flint
Chert (Silicon Dioxide, SiO2)
Petrified Wood
Silicified Wood (primarily Chalcedony or Quartz, SiO2)
Shale or Siltstone
Sedimentary Clastic Rock (Variable mineral composition including quartz and clay minerals)
Fossilized Coral
Scleractinia (fossil order), primarily Calcium Carbonate (CaCO3)
River Stone (likely Mudstone or Siltstone)
Lutite (Clastic sedimentary rock composed of clay and silt-sized particles)
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Petrified Wood (Silicified Wood)
Silicified Wood / Silicon Dioxide (SiO2)
Petrified Wood
Silicified wood (Quartz/Chalcedony - SiO2)
Petrified Wood
Silicified Wood (SiO2)
Pickled Dragon Eggs (Fictional Interpretation: Purple Agate or Amethyst Geodes)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Mookaite Jasper
Silicified Radiolarite (SiO2)
Chert (and Flint variant)
Chert (SiO2)
Fossiliferous Limestone (Shell Fragment)
Biogenic Limestone (Calcium Carbonate / CaCO3)
Slate
Slate (Foliated metamorphic rock)
Shale
Mudstone (composed primarily of clay minerals like kaolinite, illite, and smectite, with quartz and calcite)
Petrified Wood
Silicified Wood (SiO2 - Silicon Dioxide)
Chert / River Jasper
Microcrystalline Quartz (SiO2)
Chert (Nodule)
Chert (composition: SiO2)
Coral Fossil (Petrified Coral)
Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)
Shale (with minor calcite veining)
Clastic sedimentary rock (primarily clay minerals and quartz)
Jasper with Quartz Vein
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Chert (Nodule)
Silicon Dioxide (SiO2)
Fossil Shell (Bivalve)
Class Bivalvia (Likely a member of the Ostreidae or Gryphaeidae family), CaCO3
Petrified Wood
Silicified Wood (primarily SiO2)