Chert (Green variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Category
Organic Gemstone (Often Associated With Sedimentary Sequences)
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
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Polished/tumbled calcite
Calcite (calcium carbonate, CaCO₃)
mineral
Chert with Quartz Vein
Silicon dioxide (SiO2)
sedimentary
Chert / Greenstone
Silicon Dioxide (SiO2) with impurities
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Jadeite
NaAlSi2O6 (Sodium Aluminum Silicate)
mineral
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Quartz Vein in Host Rock (Gneiss/Schist)
Silicon Dioxide (SiO2) within a metamorphic matrix
metamorphic
Fossiliferous Limestone with Fossil Fragment
Fossiliferous Limestone (CaCO3 with organic remains)
fossil
Hag Stone
Perforated sedimentary rock (typically flint, chert, or limestone)
sedimentary
Chert (and Flint)
Silicon Dioxide (SiO2)
sedimentary
Chert Pebble
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Pyrite
Pyrite (Iron Disulfide), FeS2
Mineral
Pearl
Calcium carbonate (Aragonite/Calcite) - CaCO3
gemstone
Amazonite
Amazonite (KAlSi3O8)
mineral
Chert (River Pebble)
Microcrystalline silica (SiO2)
sedimentary
Tumbled amber-like inclusion
Likely amber (fossilized tree resin; complex polymer), but identification is uncertain from the image
gemstone
Limestone (Fossiliferous)
Sedimentary Carbonate Rock (CaCO3)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Fluorite (often referred to casually as 'Fluorspar' in industrial contexts)
Fluorite (CaF2)
Mineral
Horse Chestnut (Buckeye seed)
Aesculus hippocastanum seed
Organic (Non-geological)
Chert (River Pebble)
Microcrystalline Silica (SiO2)
sedimentary
Chert (or Limestone)
Sedimentary Cryptocrystalline Quartz (SiO2) or Calcium Carbonate (CaCO3)
sedimentary
Chert with Quartz Vein
Microcrystalline Quartz (SiO2)
sedimentary
Pyrite in Shale
Iron Sulfide (FeS2) in Argillaceous Shale
sedimentary
Liesegang Ring Siltstone
Siltstone with iron oxide Liesegang bands
sedimentary
Shale (possibly Carbonaceous or Oil Shale)
Laminated Mudstone (primarily clay minerals and quartz)
sedimentary
Turquoise and Spiny Oyster (Heishi style beads)
Turquoise (CuAl6(PO4)4(OH)8·4H2O) and Spondylus (Spiny Oyster shell)
mineral and organic gemstone
Chert (Pink Jasper variant)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Iron-stained)
Microcrystalline Silica (SiO2)
sedimentary
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Pyrite on Limestone
Iron Disulfide (FeS2) in Calcium Carbonate (CaCO3) matrix
sedimentary (matrix) / mineral (inclusion)
Limestone pebble
Sedimentary rock composed mainly of calcium carbonate (CaCO3)
sedimentary
Moqui Marble (Shaman Stone)
Ironstone Concretion (Goethite/Hematite Shell)
sedimentary
Chert (potentially Jasper/Common Opal mixture)
Microcrystalline Quartz (SiO2)
sedimentary
Fossilized Echinoid (Sea Urchin)
Echinoidea (Class) - Often found as Micraster or Clypeaster specimens
sedimentary
Chert (Chert / Flint)
Silicon dioxide (SiO2) - Microcrystalline quartz
sedimentary
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Fossiliferous Limestone (Crinoid stem)
CaCO3 (Calcium Carbonate) with Fossil Inclusions
sedimentary
Banded Chert (Jasper)
Silicon Dioxide (SiO2)
sedimentary
Chert (specifically Banded Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (River Pebble)
Microcrystalline silica (SiO2)
sedimentary