Glauconite (Greensand Articulated Sandstone)
Glauconite ((K, Na)(Fe, Al, Mg)2(Si, Al)4O10(OH)2)
sedimentary
Category
Organic (Geological Relative)
Browse organic (geological relative) specimens identified by the Rock Identifier community.
Fossilized sea-shell fragment, likely belemnite or rudist-like carbonate fossil
Indeterminate calcitic fossil in limestone; possible belemnite rostrum (Belemnitida)
fossil
Vesicular basalt (scoria-like volcanic rock)
Basalt, chiefly plagioclase feldspar, pyroxene, and iron-rich minerals; abundant vesicles from escaping volcanic gas
igneous
Carved pyrite frog or toad
Pyrite (iron disulfide, FeS₂), likely a carved massive aggregate
mineral
Fossil bone fragment, likely vertebrate limb or rib bone
Fossilized bone (apatite-rich hydroxyapatite, Ca₅(PO₄)₃OH); exact taxon indeterminate
fossil
Chert (Yellow Jasper variant)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Fossiliferous Limestone
CaCO3 (principally Calcite or Aragonite)
sedimentary
Coral Fossil (Scleractinia)
Scleractinia (Order), primarily CaCO3 (Aragonite or Calcite)
sedimentary
Chert (specifically Jasper/Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (and Jasper/Chalcedony variety)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Picasso Stone
Metamorphosed Calcium Carbonate (Limestone)
sedimentary
Basalt
Extrusive Mafic Igneous Rock
igneous
Fossil Bivalve / Ostreid Shell (Hag Stone / Perforated Pebble)
Phylum Mollusca, Class Bivalvia
fossil
Manganese Dendrite on Siltstone
Manganese Oxide (pyrolusite or psilomelane) Dendrites
mineral/sedimentary
Fossiliferous Limestone / Fossil Fragment
Calcium Carbonate Matrix with Biogenic Inclusions (CaCO3)
fossil
Chert / Flint
Silicon Dioxide (SiO2)
sedimentary
Chert / Flint
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Jasper)
Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
sedimentary
Green Jasper
Microcrystalline Quartz (Chalcedony), SiO2
sedimentary
Pyrite
Iron Disulfide (FeS2)
mineral
Pearl
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
mineral
Chert (Jasper variety)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Pyrite
Iron Disulfide (FeS2)
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Vesicular Basalt (Scoria)
Basalt (Extrusive Igneous Rock)
igneous
Chert Nodules in Limestone
Cryptocrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Fluorite (likely Green Fluorite variant)
Calcium Fluoride (CaF2)
mineral
Sand Dollar Fossil (Echinoidea)
Class Echinoidea (likely order Clypeasteroida), CaCO3 (Calcite)
sedimentary
Blue-green copper mineral-bearing rock, likely chrysocolla with malachite
Chrysocolla (hydrated copper aluminosilicate, approximately (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O) with malachite (Cu₂CO₃(OH)₂), possibly in altered host rock
mineral
Tumbled amethyst
Amethyst, purple quartz (SiO₂)
gemstone
Glauconite (Greensand)
Glauconite (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Limonite and Goethite (Ironstone)
Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)
sedimentary
Amazonite
KAlSi3O8 (Potassium Aluminum Silicate) - a variety of Microcline Feldspar
mineral
Trilobite Pygidium (Tail Segment)
Phylum Arthropoda, Class Trilobita (likely order Phacopida)
sedimentary (fossil)
Flint with Fossil Inclusion
Cryptocrystalline quartz (SiO2) enclosing fossilized organic remains
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary