Ironstone Concretion
Ferruginous Sandstone / Iron-rich Sedimentary Rock
Category
Browse organic (geological relative) specimens identified by the Rock Identifier community.
Ironstone Concretion
Ferruginous Sandstone / Iron-rich Sedimentary Rock
Black Pearl (Tahitian Pearl)
Aragonite / Calcite (CaCO3) with Conchiolin
Epidote (Unakite-related)
Epidote (Ca2(Al,Fe)3(SiO4)3(OH))
Basalt with Amygdule
Aphanitic Mafic Volcanic Rock (Basalt) with Zeolite/Quartz Infill
Basalt
Basalt (composition of plagioclase, pyroxene, and olivine)
Sandstone Geode (Ironstone Concretion)
Arenite with Limonite/Hematite matrix (SiO2 with Fe-oxides)
Basalt
Basalt
Horse Chestnut (Buckeye seed)
Aesculus hippocastanum seed
Ironstone Concretion / Limonite Node
Ferruginous Sedimentary Rock (composed primarily of Limonite FeO(OH)·nH2O and Goethite)
Fluorite
Fluorite (Calcium Fluoride, CaF2)
Vesicular Basalt
Extrusive mafic igneous rock (primarily Plagioclase feldspar and Pyroxene)
Pink Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
Ironstone Concretion (Limonite/Goethite)
Goethite-rich Concretion (FeO(OH))
Green Fluorite
Fluorite (Calcium Fluoride, CaF2)
Basalt
Mafic volcanic rock (primarily plagioclase, pyroxene, and olivine)
Ironstone Concretion
Siderite or Hematite-bonded Concretion
Greenstone
Greenschist (primarily composed of chlorite, actinolite, and epidote)
Blue Apatite
Fluorapatite / Chlorapatite [Ca5(PO4)3(F,Cl,OH)]
Fluorite
Calcium Fluoride (CaF2)
Brown Jasper (Likely)
Jasper (Cryptocrystalline Silicon Dioxide - SiO2)
Coarse-Grained Marble
Recrystallized Limestone (Major component: CaCO3)
Yellow Calcite
Calcium Carbonate (CaCO3)
Pyrite
Iron Sulfide (FeS2)
Gold Nugget
Native Gold (Au)
Basalt
Basalt (comprising plagioclase, pyroxene, and olivine)
Ironstone Nodules / Siderite Concretion
Siderite (FeCO3) / Ferruginous Septarian Concretion
Vesicular Basalt
Vesicular Basalt
Green Calcite
Calcite (CaCO3)
Pegmatite
Granitic Pegmatite
Amber
Resinite / Fossilized Tree Resin
Green Calcite (often commercially called Green Onyx)
Calcium Carbonate (CaCO3)
Basalt (Vesicular and Scoria)
Basalt (extrusive volcanic rock)
Freshwater Pearl
Aragonite / Biogenic Calcium Carbonate (CaCO3)
Basalt
Basalt (Mafic Extrusive Igneous Rock)
Ammonite Fossil
Ammonoidea (subclass)
Basalt
Basalt (extrusive volcanic rock)
Serpentine, likely a variety of Chrysoprase (green chalcedony) or a similar translucent green mineral.
Serpentine Group Minerals (e.g., Antigorite, Lizardite) or Chalcedony (SiO2) with nickel impurities for Chrysoprase green.
Basalt with Calcite Veins
Basalt (containing CaCO3 inclusions)
Naga Silver-Inlaid Ebony and Bone/Horn Beads
Diospyros (Ebony) or Keratin (Horn) with Silver/White-Metal Inlay
Basalt
Basalt (Aphanitic Mafic Volcanic Rock)
Red Coral (Precious Coral)
Corallium rubrum (Calcium Carbonate, CaCO3)