Limonitic Sandstone with Inclusion
Limonitic Quartz Sandstone (primarily SiO2 with FeO(OH)·nH2O)
sedimentary
Category
Mineral Like Biological Tissue
Browse mineral like biological tissue specimens identified by the Rock Identifier community.
Learn about Mineral Like Biological Tissue in the encyclopedia
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Pearl
Calcium carbonate (CaCO3) in the form of aragonite
gemstone
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Fossilized Fish Skeleton in Matrix
Vertebrata (Class: Actinopterygii), typically found in limestone or shale matrices
sedimentary
Biological Bone (Patella/Knee)
Patella (part of the Human Skeletal System)
Organic Structure (Not a Rock)
Amber
Succinite (approximate formula C10H16O)
mineral
Red Moss Agate (Jasper)
Silicon Dioxide (SiO2) with Iron Oxide inclusions
sedimentary
Silicified oyster fossil
Fossil oyster shell, commonly Ostrea or Crassostrea, replaced or encrusted by chalcedony/quartz
fossil
Chert
Silicon dioxide (SiO2)
sedimentary
Chert / Jasper Pebble
Microcrystalline Quartz (SiO2)
sedimentary
Lepidodendron Fossil (Scale Tree)
Lepidodendron sp.
fossil
Bivalve Fossil (Clam)
Class Bivalvia, likely Mercenaria or similar genus
fossil
Fossilized Brachiopod
Phylum Brachiopoda (replaced by Calcite/CaCO3)
sedimentary
Amber (in Matrix/Shale)
Amber (Fossilized Tree Resin)
mineral
Fossilized Brachiopod
Phylum Brachiopoda (General mineral composition: Calcite/CaCO₃ or Silica/SiO₂)
sedimentary
Amber
Succinite (C10H16O)
Mineraloid
Septarian Nodule
Septarian Concretion (Composition: Calcite, Aragonite, and Limestone/Clay)
sedimentary
Kidney Stone (Urolith)
Calculus renalis (Biogenic mineral aggregate)
mineral
Fossilized Coral
Anthozoa (Fossilized)
Sedimentary / Fossil
Chert (Flint)
Microcrystalline silica (SiO2)
sedimentary
Fossil tooth, likely mosasaur or large marine reptile tooth
Fossilized reptilian tooth; exact taxon requires diagnostic views and locality
fossil
Polished fossil shell fragment (likely ammonite or bivalve)
Fossilized mollusk shell; likely aragonite/calcite replaced by silica or iron-rich minerals
fossil
Polished moss agate cabochon
Moss agate, a translucent chalcedony variety (microcrystalline quartz, SiO₂) with inclusions of chlorite, amphibole, or manganese/iron oxides
gemstone
Freshwater Pearl
Aragonite / Biogenic Calcium Carbonate (CaCO3)
mineral
Bivalve Fossil (Clam)
Class Bivalvia (e.g., Mercenaria or similar genus)
fossil
Tufa (Calcareous Tufa)
Calcareous Tufa (Precipitated CaCO3)
sedimentary
Calcite
Calcium Carbonate (CaCO3)
mineral
Fossilized bivalve shell
Bivalvia (likely a venerid or similar clam); shell composed mainly of CaCO₃ as aragonite/calcite
fossil
Fossil gastropod shell
Spiral marine gastropod fossil; likely a small ammonite-like or gastropod shell, exact taxon indeterminate
fossil
Aragonite
Aragonite (Calcium Carbonate - CaCO3)
mineral
Likely petrified wood or silicified fossil fragment
Silicified wood; predominantly microcrystalline quartz (SiO₂)
fossil
Fossilized bivalve shell
Bivalvia indeterminate; likely a fossil clam or cockle
fossil
Ironstone Concretion
Ironstone (Limonite/Goethite Concretion)
sedimentary
Fossiliferous Limestone (with Crinoids/Coral)
Fossiliferous Limestone (CaCO3)
sedimentary
Fossilized bivalve shell
Recrystallized calcium-carbonate shell, commonly fossil oyster or clam (Bivalvia)
fossil
Chert
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Vesicular Basalt (Scoria)
Basalt with vesicular texture
igneous
Pearl
Organic gemstone (Calcium carbonate - CaCO3)
mineral
Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite organic gemstone
mineral
Pink Pearl
Calcium Carbonate (Aragonite/Calcite) with Conchiolin (CaCO3)
mineral
Pearl
Calcium Carbonate (CaCO3) + Conchiolin
mineral
Limestone with Calcite Veins
Calcite-veined Argillaceous Limestone
sedimentary