Limitation Concretion
Ironstone Concretion (Goethite/Limonite)
sedimentary
Category
Mineral Like Biological Tissue
Browse mineral like biological tissue specimens identified by the Rock Identifier community.
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Bivalve Fossil (Brachiopod or Scallop)
Class Bivalvia (or potentially Phylum Brachiopoda)
fossil
Petrified Wood
Silicified Wood (SiO2 permineralization)
fossil
Petrified Wood
Silicified wood (primarily quartz, SiO2)
sedimentary
Dendritic Limestone
Calcite with Manganese Oxide (Manganese Dendrites)
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Sandstone with Lichen and Iron Oxide Staining
Quartz Arenite / Sandstone
sedimentary
Natural Pearl
Calcium carbonate (primarily Aragonite and Conchiolin), CaCO3
mineral
Petrified Wood
Silicified Wood (Permineralized organic tissue)
fossil
Chert or Flint
Silicon dioxide (SiO2)
sedimentary
Petrified Wood
Silicified wood (Quartz replacement)
fossil
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Sandstone concretion
Arenite sedimentary rock (concretion/nodule)
sedimentary
Fossil Shark Tooth
Squalicorax (likely Squalicorax pristodontus or Squalicorax falcatus)
fossil
Pearl
Aragonite (CaCO3) with Conchiolin
mineral
Precious Red Coral
Corallium rubrum / Corallium japonicum
mineral (organic gemstone)
Amber
Succinite (specifically Baltic Amber) - Formula: C10H16O (approximate)
Organic Mineraloid
Yellow Calcite
Calcium Carbonate (CaCO3)
mineral
Amber
Succinite (organic hydrocarbon)
mineraloid
Pearl
Calcium Carbonate (Aragonite) - CaCO3
mineral
Pearl
Calcium Carbonate (Aragonite/Calcite) with Conchiolin (CaCO3)
mineral
Pearl (as a Biogenic Mineral)
Calcium Carbonate (mostly Aragonite) with Conchiolin; CaCO3
mineral
Chert with Iron Oxide Staining
Microcrystalline Quartz (SiO2) with Limonite/Goethite staining
sedimentary
Amber
Succinite (Fossilized Resin)
fossil
Sandstone with Algae Growth
Arenite with Chlorophyta/Lichen
sedimentary
Amber
Succinite (fossilized resin)
mineral
Fossilized Shark Tooth (Partial) or Coprolite
Elasmobranchii (fossil) or Coprolite (trace fossil)
fossil
Limestone with Lichen/Algae
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Limonite (Hydrated Iron Oxide / Bog Iron)
FeO(OH)·nH2O
Mineral (Sedimentary context)
Sandstone (with Lichen)
Arenite (composed primarily of SiO2)
sedimentary
Chert (with potential fossil inclusion)
Microcrystalline Quartz (SiO2)
sedimentary
Amber (Copal)
Succinite (fossilized tree resin)
mineral
Tonsil Stone (Tonsillolith)
Calcium phosphate / Calcium carbonate biomineral
mineral
Rough Amber (likely Copal or immature Amber)
Organic gemstone / Succinite (if Baltic)
mineral
Gravel or Pebble
Clastic Sedimentary Grain (typically composed of Quartz or Silicate minerals)
sedimentary
Amber
Succinates (Fossilized Tree Resin)
fossil
Amethyst
Amethyst (Silicon Dioxide, SiO2 + Fe)
mineral
Pearl
Organic Mineral (CaCO3 with conchiolin)
mineral
Fossil Coral
Anthozoa (Scleractinia)
fossil
Sandstone concretion (Ironstone-stained)
Arenite with Limonite/Hematite staining (Silica-based with Iron Oxides)
sedimentary
Amber
Succinate (Succinite for Baltic varieties)
Organic Mineraloid