Chert (Brown variety)
Silicon Dioxide (SiO2)
Category
Browse organic gemstone (sedimentary classification) specimens identified by the Rock Identifier community.
Chert (Brown variety)
Silicon Dioxide (SiO2)
Fossiliferous Limestone (Crinoidal)
Calcium Carbonate (CaCO3) - Limestone containing bioclasts
Fossilized Shark Tooth (Partial)
Elasmobranchii (fossil tooth fragment)
Chert Pebble with Quartz Veining
Microcrystalline Quartz (SiO2)
Banded Chert (River Siltstone)
Microcrystalline Quartz (SiO2)
Glauconitic Sandstone (Greensand)
Glauconitic Sandstone ((K, Na)(Fe3+, Al, Mg)2(Si, Al)4O10(OH)2)
Chert (Jasper variation)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Chert (Quartz Variety)
Silicon Dioxide (SiO2)
Chert (Black Chert/Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Fossiliferous Limestone (containing Brachiopods)
Biogenic Limestone (Calcium Carbonate, CaCO3)
Mixed Mineral Collection
Multi-mineral Assemblage (Quartz, Jasper, Obsidian, Pyrite, etc.)
Carnelian
Carnelian (SiO2)
Jasper
Silicon dioxide (SiO2) with impurities
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Petrified Rugose Coral (Horn Coral)
Order Rugosa (extinct coral)
Anthracite Coal
Anthracite (Carbon-based organic sedimentary/metamorphic rock)
Coal (Anthracite)
Anthracite (Carbon-based organic sedimentary/metamorphic rock)
Botryoidal Chalcedony
Silicon Dioxide (SiO2)
Variscite in Matrix
Variscite (AlPO4 · 2H2O)
Carnelian
Carnelian (subset of Chalcedony); SiO2 with Iron Oxide impurities
Quartz (Milky/Common)
Silicon Dioxide (SiO2)
Blue Chalcedony
Cryptocrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide and organic impurities
Petrified Wood
Silicified Wood (SiO2)
Jasper
Silicon Dioxide (SiO2)
Red Jasper (with Chert/Quartz)
Silicon Dioxide (SiO2)
Chalcedony (Botryoidal)
Silicon Dioxide (SiO2)
Coral Fossil (Agatized Coral or Petoskey Stone)
Hexagonaria percarinata (if Petoskey) or generally Scleractinia (Agatized Coral)
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide and organic impurities
Black Opal
Hydrated Amorphous Silica (SiO2 "n" H2O)
Zebra Marble
Metamorphosed Alabaster/Limestone (CaCO3)
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Caribbean Calcite
Calcium Carbonate with Argonite (CaCO3)
Yellow Jasper
Jasper (Silicon Dioxide, SiO2)
Petrified Wood
Silicified Wood (SiO2)
Limonite-stained Chert
Microcrystalline Quartz (SiO2) with Hydrated Iron Oxides (FeO(OH)·nH2O)
Chert (White/Light Tan)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Jasper
Silicon dioxide (SiO2)
Rhodochrosite
Manganese Carbonate (MnCO3)
Garnet Schist
Almandine Garnet in Schist (X3Al2(SiO4)3)
Chert with Calcite Veining
Microcrystalline Quartz (SiO2) with Calcium Carbonate (CaCO3) veins