Banded Chert (or Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Category
Organic Gemstone (Sedimentary Associations)
Browse organic gemstone (sedimentary associations) specimens identified by the Rock Identifier community.
Chert (Brown variety)
Silicon Dioxide (SiO2)
sedimentary
Fossiliferous Limestone (Crinoidal)
Calcium Carbonate (CaCO3) - Limestone containing bioclasts
sedimentary
Chert (Quartz Variety)
Silicon Dioxide (SiO2)
sedimentary
Chert Pebble with Quartz Veining
Microcrystalline Quartz (SiO2)
sedimentary
Banded Chert (River Siltstone)
Microcrystalline Quartz (SiO2)
sedimentary
Glauconitic Sandstone (Greensand)
Glauconitic Sandstone ((K, Na)(Fe3+, Al, Mg)2(Si, Al)4O10(OH)2)
sedimentary
Chert (Black Chert/Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Fossiliferous Limestone (containing Brachiopods)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Anthracite Coal
Anthracite (Carbon-based organic sedimentary/metamorphic rock)
metamorphic
Coal (Anthracite)
Anthracite (Carbon-based organic sedimentary/metamorphic rock)
metamorphic
Jasper
Silicon dioxide (SiO2)
Sedimentary / Mineral
Jasper
Silicon dioxide (SiO2) with impurities
sedimentary
Carnelian
Carnelian (SiO2)
mineral
Zebra Marble
Metamorphosed Alabaster/Limestone (CaCO3)
metamorphic
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
sedimentary
Botryoidal Chalcedony
Silicon Dioxide (SiO2)
mineral
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Carnelian
Carnelian (subset of Chalcedony); SiO2 with Iron Oxide impurities
mineral
Variscite in Matrix
Variscite (AlPO4 · 2H2O)
mineral
Chert (White/Light Tan)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide and organic impurities
sedimentary
Caribbean Calcite
Calcium Carbonate with Argonite (CaCO3)
mineral
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Graphite Schist
C (Carbonaceous Schist)
metamorphic
Blue Chalcedony
Cryptocrystalline Quartz (SiO2)
mineral
Quartz (Milky/Common)
Silicon Dioxide (SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
sedimentary
Green Jasper (with Quartz veining)
Jasper (Silica-rich microcrystalline variety of Quartz), formula: SiO2
sedimentary
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide and organic impurities
sedimentary
Precious Opal
Hydrated silica (SiO2·nH2O)
mineraloid
Banded Chert (or River Jasper)
Microcrystalline Quartz (SiO2) with iron oxide impurities
sedimentary
Chert (variously identified as Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary
Septarian Nodule (Thunder Egg)
Septarian Concretion (CaCO3 + CaMg(CO3)2 + SiO2)
sedimentary
Chert (Iron-stained)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Jasper
Silicon dioxide (SiO2)
sedimentary
Coral Fossil (Agatized Coral or Petoskey Stone)
Hexagonaria percarinata (if Petoskey) or generally Scleractinia (Agatized Coral)
Sedimentary/Fossil
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary