Chert (variations include Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Category
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
Chert (variations include Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Limestone
Calcium Carbonate (CaCO3)
Limestone
Calcium Carbonate (CaCO3)
Rhodochrosite
Manganese carbonate (MnCO3)
Coquina (Fossiliferous Limestone)
Coquina (Organic Clastic Limestone)
Amber (in Matrix/Shale)
Amber (Fossilized Tree Resin)
Fluorite
Calcium Fluoride (CaF2)
Fossiliferous Limestone (Coquina / Shell Limestone)
Biogenic Limestone (CaCO3)
Chert (and Limestone)
Chert (consisting of Microcrystalline Quartz, SiO2)
Tufa (Limestone)
Calcareous Tufa (CaCO3)
Rhodochrosite
Manganese carbonate (MnCO3)
Jasper with Agate Inclusions
Jasper (Silicon Dioxide, SiO2) with Chalcedony/Agate
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Honey Calcite Sphere
Calcium Carbonate (CaCO3)
Kyanite (Blue Kyanite)
Kyanite (Al2SiO5)
Rhodochrosite
Manganese Carbonate (MnCO3)
Chert (Yellow Jasper variant)
Microcrystalline Quartz (SiO2)
Chert (Chert Nodule with Cortex)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Greenstone (Greywacke or Nephrite Jade variant)
Metamorphosed mafic igneous or sedimentary rock (e.g., Actinolite-Chlorite Schist)
Ferruginous Sandstone
Sandstone with Iron Oxide (Limonite/Goethite)
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
Flint
Chert (a form of cryptocrystalline quartz, chemical formula SiO₂)
Serpentine (Serpentinite)
Antigorite, Lizardite, or Chrysotile; (Mg,Fe)3Si2O5(OH)4
Dearest Jewelry (Multigemstone)
Combination of Diamond (C), Emerald (Be3Al2Si6O18), Amethyst/Rock Crystal (SiO2), Ruby (Al2O3), Emerald (Be3Al2Si6O18), Sapphire (Al2O3), and Topaz (Al2SiO4(F,OH)2)
Amber (Copal)
Fossilized Tree Resin (C10H16O)
Rhodonite
Manganese Silicate (Mn,Fe,Mg,Ca)SiO3
Black Pearl (Tahitian or Irradiated Type)
Organic gemstone (Calcium Carbonate with Conchiolin Binding)
Red Jasper
Jasper (Silicon Dioxide) - SiO2
Yellow Calcite
Calcium Carbonate (CaCO3)
Dragon Blood Jasper
Epidote with Red Piedmontite (Chalcedony/Quartz variant)
Yellow Jasper
Silicon Dioxide (SiO2) with Goethite/Iron Oxide inclusions
Jasper
Silicon dioxide (SiO2)
Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3 with Carotenoid pigments)
Amber
Organic gemstone (Succinite is common if from the Baltic)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified wood (primarily SiO2 - Silicon Dioxide/Quartz)
Travertine (Tufa)
Calcium Carbonate (CaCO3)
Carnelian Agate
Carnelian (SiO2 with iron oxide impurities)
Jasper
Silicon dioxide (SiO2)
Chert (or Flint)
Chert (cryptocrystalline quartz), SiO2