Shale (possibly Carbonaceous or Oil Shale)
Laminated Mudstone (primarily clay minerals and quartz)
sedimentary
Category
Organic Materia (Not A Rock Or Mineral)
Browse organic materia (not a rock or mineral) specimens identified by the Rock Identifier community.
Learn about Organic Materia (Not A Rock Or Mineral) in the encyclopedia
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Chert (Chert / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert Pebble
Microcrystalline Quartz (SiO2)
sedimentary
Chert with Quartz Veining
Silicon Dioxide (SiO2)
sedimentary
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 cement)
sedimentary
Petrified Wood
Silicified Wood (Silicon Dioxide - SiO2)
fossil
Shale
Fissile Clay-dominant Mudrock (SiO2, Al2O3, K2O, Na2O, CaO, MgO)
sedimentary
Chert (Jasper/Flint Pebble)
Microcrystalline quartz (SiO2)
sedimentary
Petrified Wood
Silicified wood (Quartz replacement of organic wood structure)
fossil
Petrified Wood
Silicon Dioxide (SiO2)
fossil
Travertine (Tufa)
Chemical Limestone (CaCO3)
sedimentary
Chert (Green Chert)
Microcrystalline silica (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, formula: SiO2)
sedimentary
Precious Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
mineral
Amber (Raw)
Succinite (Fossilized Resin)
mineraloid
Green Jasper
Silicon Dioxide (SiO2) with impurities
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Sandstone (likely Fossilized Wood or Concrete Simulacrum)
Arenite / Silicified Wood / Anthropogenic Concrete
sedimentary
Banded Chert (Ironstone type)
Silicon Dioxide (SiO2) with Iron Oxide inclusions
sedimentary
Fossilized Dinosaur Bone
Perineralized Bone (Fluorapatite/Quartz replacement)
fossil
Chert (Jasper/Mudstone variety with Oxidation)
Silicon dioxide (SiO2)
sedimentary
Chert (varietal: Flint/Jasper mix)
Hydrous Silica (SiO2)
sedimentary
Banded Sedimentary Rock (Siltstone/Mudstone with concretion)
Siltstone with Ferruginous Banding
sedimentary
Fossil bivalve shell
Likely an extinct or modern-like ribbed cockle/scallop; exact genus requires locality and diagnostic hinge features
fossil
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Chert (Jasper/Flint Pebble)
Microcrystalline quartz (SiO2)
sedimentary
Chert (Flint)
SiO2 (Microcrystalline Quartz)
sedimentary
Geode (Unopened)
Silica-rich concretion (SiO2)
sedimentary
Chert / River Pebble
Silicon Dioxide (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
sedimentary
Septarian Nodule (Dragon Stone)
Septarian concretion (composition: CaCO3 - Calcite, Aragonite, and Siderite/Limestone)
sedimentary
Moss Agate Sphere
Silicon Dioxide (SiO2) with inclusions
mineral
Pink Opal (Common Opal)
Amorphous Hydrated Silica (SiO2·nH2O)
mineral
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (varieties include Flint and Jasper)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Pyrite Geode (Sparkling Druzy)
Iron Sulfide (FeS2) in Sedimentary Nodule
mineral
Baltic Amber (Butterscotch or Egg Yolk Variety)
Succinite (chemical formula: C10H16O)
Organic Gemstone (not a rock or mineral)
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Septarian Nodule (Polished)
Septarian concretion (Calcite, Aragonite, Limestone)
sedimentary
Chert (Sedimentary Rock)
Silicon Dioxide (SiO2)
sedimentary
Fossilized Echinoid / Sea Urchin Internal Mold
Echinoidea internal cast (steinkern)
fossil