Ironstone Concretion (Iron-rich Mudstone)
Siderite / Geothite concretion (FeCO3 / FeO(OH))
sedimentary
Category
Organic Mineral
Browse organic mineral specimens identified by the Rock Identifier community.
Learn about Organic Mineral in the encyclopedia
View all →
Green Jasper
Microcrystalline Quartz (SiO2) with mineral inclusions
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Green Moss Agate
Silicon Dioxide (SiO2) with Mineral Inclusions
sedimentary
Ironstone Concretion (Limonite/Goethite)
Goethite/Limonite concretion (FeO(OH)·nH2O)
sedimentary
Fossilized Shark Teeth
Otodus sp. (Eocene Sand Tiger/Mackerel Shark)
fossil
Shark Tooth Fossil
Carcharocles megalodon or similar fossilized shark tooth
fossil
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Fossilized Coral (Petoskey Stone or Rugose Coral)
Antophyllum (Hexagonaria) or Scleractinia (CaCO3)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Yellow Jasper
Quartz (Silicon Dioxide, SiO2 with impurities)
sedimentary
Pitted Limestone
Calcium Carbonate (CaCO3)
sedimentary
Shale with Coprolite influence
Argillaceous sedimentary rock (Shale/Mudstone)
sedimentary
Amber / Copal
Fossilized Tree Resin (Succinate)
Mineraloid
Chert (with potential fossil inclusion)
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone with Iron Oxide Concretion
Arenite with Hematite/Goethite Concretion
sedimentary
Ferruginous Sandstone with Concretion
Sandstone (SiO2 dominated with Fe2O3 cement)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Black Onyx
Cryptocrystalline Quartz (SiO2 with organic/iron impurities)
mineral
Blue Agate (Tumbled and Dyed)
Silicon Dioxide (SiO2) with likely organic dyes
mineral
Amber
Succinite (C10H16O)
mineral
Black Pearl (Tahitian-style Cultured Pearl)
Calcium Carbonate (Aragonite) with Conchiolin (CaCO3)
mineral
Green Fluorite
Fluorite (Calcium Fluoride, CaF2)
mineral
Amber
Succinite (C10H16O)
mineral
Moss Agate
Cryptocrystalline Quartz (SiO2 with manganese or iron oxide inclusions)
mineral
Fossilized Shark Tooth (Fragment)
Elasmobranchii gen. indet.
fossil
Sandstone Concretion
Arenaceous concretion (primarily SiO2 with Fe2O3 staining)
sedimentary
Moss Agate
Silicon Dioxide (SiO2) with Chlorite/Hornblende inclusions
mineral
Amber
Succinite (specifically for Baltic amber); Chemical formula approximately C10H16O
mineral
Moss Agate
Silicon Dioxide (Chalcedony variety)
mineral
Tree Agate
Dendritic Agate (Silicon Dioxide, SiO2)
mineral
Jasper
Silicon Dioxide (SiO2) microcrystalline quartz
sedimentary
Jasper
Silicon Dioxide (SiO2) with impurities
sedimentary
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Pyrite (Pseudomorph)
Iron Sulfide (FeS2)
mineral
Petrified Wood
Silicified wood (SiO2)
fossil
Chert (Flint)
Silicon dioxide (SiO2)
sedimentary
Chert / Chalcedony
Microcrystalline Quartz (SiO2)
sedimentary
Chalcedony (Agate / Jasper Specimen)
Silicon Dioxide (SiO2)
mineral
Pyrite in Slate or Shale
Iron Sulfide (FeS2) in Argillaceous Matrix
mineral