Fossiliferous Limestone Pebble
Calcite-rich Fossiliferous Marine Limestone
fossil
Category
Organic Mineraloid
Browse organic mineraloid specimens identified by the Rock Identifier community.
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Chert (Jasper/River Stone)
Silicon dioxide (SiO2) - Microcrystalline quartz
sedimentary
Fossiliferous Limestone
Bioclastic Limestone (CaCO3)
sedimentary
Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
metamorphic
Chert
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Fossilized Horn Coral
Order Rugosa (Rugose Coral)
sedimentary
Coral Rock (Coquina)
Biogenic Limestone (Calcium Carbonate - CaCO3)
sedimentary
Sandstone (Weathered Coastal Boulder)
Arenite (composed primarily of SiO2)
sedimentary
Honey calcite (orange calcite)
Calcite, calcium carbonate (CaCO₃)
mineral
Moss Agate
SiO2 (Cryptocrystalline Quartz)
gemstone
Weathered dark flint (chert) pebble
Microcrystalline quartz (SiO₂), commonly called flint or chert
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified Wood (SiO2)
mineral
Sandstone Chert Concretion
Silica-cemented Concretion (primarily SiO2)
sedimentary
Amber
Succinite
mineral
Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide
mineral
Precious Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Mineral (Organic Gemstone)
Amber with inclusion
Amber (Fossilized Tree Resin)
mineral
Chert (specifically Gray Chert)
Silicon Dioxide (SiO2)
sedimentary
Sandstone with Vitrinite/Coal inclusions
Arenite with Carbonaceous inclusions
sedimentary
Chert / Flint (with Crinoid Stem Molds)
Microcrystalline Quartz (SiO2)
sedimentary
Ferruginous Sandstone Concretion (Ironstone Phosphorite)
Ferruginous Sandstone (variable Fe-oxide/hydroxide composition)
sedimentary
Moss Agate
Chalcedony (Silicon Dioxide - SiO2) with inclusions
Mineral
Chert (Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone with Quartz Crystal Infill
Quartz-cemented quartz arenite
sedimentary
Coal (Bituminous Coal)
Caustobiolith / Sedimentary Rock
sedimentary
Anthracite Coal
Anthracite (Carbon-based metamorphic rock, 86-97% C)
metamorphic
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
sedimentary
Stromatolite (Fossiliferous Limestone)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Fossilized coral (likely honeycomb or branching coral)
Fossil coral; probable Scleractinia or Tabulata, composition mainly microcrystalline CaCO₃
fossil
Moss Agate
Silicon Dioxide (Chalcedony variety)
mineral
Amber
Succinite / Fossilized Tree Resin
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Banded Chert / Flint Pebble
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily Quartz/SiO2)
fossil
Green Moss Agate
Agate (Silicon Dioxide, SiO2) with inclusions
mineral
Moss Agate
Silicon Dioxide (SiO2) with Chlorite/Hornblende inclusions
mineral
Amber
Succinite (specifically for Baltic amber); Chemical formula approximately C10H16O
mineral
Aragonite (Star Cluster or Twinned variety)
Aragonite (Calcium Carbonate, CaCO3)
mineral
Travertine (Tufa)
Chemical Sedimentary Rock / Travertine (CaCO3)
sedimentary
Moss Agate
Agate (Silicon Dioxide, SiO2) with dendritic inclusions
sedimentary