Pyritic Mudstone
Argillaceous rock (FeS2)
Category
Browse organic gemstone specimens identified by the Rock Identifier community.
Pyritic Mudstone
Argillaceous rock (FeS2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Chert (with Limestone and Iron Oxide staining)
Cryptocrystalline Quartz (SiO2)
Quartzite and Milky Quartz River Pebbles
Silicon Dioxide (SiO2)
Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxides
Amber
Succinite (C10H16O)
Rough Garnet (Almandine)
Almandine Garnet (Fe3Al2(SiO4)3)
Amber
Succinite (a specific common type) or Fossilized Tree Resin (C10H16O)
Peridot
Olivine (Mg, Fe)2SiO4
Moss Agate
Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxide
Tahitian Pearl
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
Anthracite Coal
Anthracite (Carbon-based metamorphic rock, 86-97% C)
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
Stromatolite (Fossiliferous Limestone)
Biogenic Limestone (Calcium Carbonate, CaCO3)
Sandstone (Weathered Coastal Boulder)
Arenite (composed primarily of SiO2)
Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
Petrified Wood
Silicified Wood (SiO2)
Fossiliferous Limestone (Coral Fossil)
Scleractinian Coral in Calcium Carbonate (CaCO3)
Peridot
Olivine ((Mg, Fe)2SiO4)
Chert (Jasper/Chalcedony)
Microcrystalline Quartz (SiO2)
Fossiliferous Limestone
Carbonate sedimentary rock (CaCO3) with bioclasts
Chert
Microcrystalline Quartz (SiO2)
Shark Tooth Fossil
Carcharodonta (order Lamniformes), likely Carcharias spp.
Chert Nodule (with Geode cavity)
Cryptocrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Chert (River Pebble)
Cryptocrystalline Quartz (SiO2)
Chert (Flint)
Silicon Dioxide (SiO2)
Chert (Jasper/Common Opal mix)
Microcrystalline Quartz (SiO2)
Shungite
Shungite (Non-crystalline carbon, C)
Banded Chert
Silicon Dioxide (SiO2)
Chert (White Chert / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Chert (Jasper variation)
Microcrystalline Quartz (SiO2)
Chert (Flint variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Pyrite Concretion
Iron Sulfide (FeS2) in Sedimentary Matrix
Calligraphy Stone
Fossiliferous Limestone (containing Hematite and Shells)
Chert (with Limestone/Carbonate matrix)
Sedimentary cryptocrystalline silica (SiO2)
Chert (Flint)
Silicon dioxide (SiO2) - Cryptocrystalline Quartz
Yellow Chert
Sedimentary cryptocrystalline quartz (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert (and/or River Pebble)
Microcrystalline quartz (SiO2)
Flint (Chert)
Cryptocrystalline Quartz (SiO2)