Chert (Jasper/Common Opal mix)
Microcrystalline Quartz (SiO2)
Category
Browse organic gemstone (sedimentary associations) specimens identified by the Rock Identifier community.
Chert (Jasper/Common Opal mix)
Microcrystalline Quartz (SiO2)
Chert (Jasper type)
Microcrystalline Quartz (SiO2)
Limestone with Chert or Siltstone bands
Sedimentary carbonate rock (CaCO3) often with siliceous impurities
Chert (Yellow Jasper variant)
Silicon Dioxide (SiO2)
Chert (Yellow/Brown variety)
Chert (SiO2)
Ironstone Concretion / Limonite Node
Goethite and Limonite (FeO(OH) nH2O)
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Basanite / Flint variety)
Microcrystalline Quartz (SiO2)
Chert (Fossiliferous)
Silicon dioxide (SiO2)
Chert (often found as Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Pyrite in Quartz
Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)
Orthoceras Fossil Limestone
Orthoceras (extinct Cephalopod fossil) in Matrix
Coquina / Shelly Limestone
Coquina (Biogenic Limestone)
Petrified Wood
Silicified Wood (SiO2)
Glauconite (Greensand Articulated Sandstone)
Glauconite ((K, Na)(Fe, Al, Mg)2(Si, Al)4O10(OH)2)
Chert (Smooth River Pebble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Chert (White Chert or Flint)
Microcrystalline Quartz (SiO2)
Pyrite (Fool's Gold) in Matrix
Iron Sulfide (FeS2)
Pyrite on Limestone
Iron Disulfide (FeS2) in Calcium Carbonate (CaCO3) matrix
Black Jasper (Black Onyx substitute)
Silicon Dioxide (SiO2) with carbonaceous impurities
Sodalite
Sodalite, Na8(Al6Si6O24)Cl2
Chert (Jasper)
Microcrystalline Quartz (SiO2)
Pearl (nacre)
Calcium Carbonate (mostly CaCO3 as Aragonite) and Conchiolin
Chert (Nodule)
Microcrystalline quartz (SiO2)
Crushed Limestone
Sedimentary Calcium Carbonate (CaCO3)
Pyrite
Iron Sulfide (FeS2)
Pyrite in Shale
Iron Sulfide (FeS2) in Sedimentary Matrix
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)
Limestone
Calcium Carbonate (CaCO3)
Shale or Siltstone
Sedimentary Clastic Rock (Variable mineral composition including quartz and clay minerals)
Chert (Brecciated Chert)
Silicon Dioxide (SiO2)
Fossil Coral (Rugose Coral Fragment)
Rugosa (extinct order of solitary and colonial corals)
Sandstone (likely Fossiliferous Sandstone)
Clastic sedimentary rock (primarily SiO2)
Fossilized Shark Tooth
Bioapatite (Calcium Hydroxyapatite) replacement
Concretionary Sandstone
Clastic Sedimentary Rock (Sandstone with secondary mineral cementation)
Green Moss Agate
Silicon Dioxide with inclusions (SiO2)
Chert (Jasper variation)
Microcrystalline Quartz (SiO2)
Coquina or Fossiliferous Limestone
Fossiliferous Calcarenite (CaCO3)