Sandstone
Arenite (SiO2 dominant)
Category
Browse organic structure (not a rock) specimens identified by the Rock Identifier community.
Sandstone
Arenite (SiO2 dominant)
Quartz Druzy (Geode Fragment)
Silicon Dioxide (SiO2)
Chert (and/or Flint)
Microcrystalline Quartz (SiO2)
Chert (Jasper variation)
Chert (SiO2)
Petrified Wood
Silicified wood (primarily quartz replacing organic cellulose)
Mammoth Tooth
Mammuthus tooth fossil
Sandstone
Arenite (Sedimentary rock)
Basalt
Extrusive Igneous Rock
Garnet Gneiss
Garnetiferous Gneiss
Serpentine
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)3(Si, Al, Fe)2O5(OH)4
Orange Quartz (or Carnelian Chalcedony)
Silicon Dioxide (SiO2)
Chert
Microcrystalline Quartz (SiO2)
Chert
Microcrystalline Quartz (SiO2)
Fossilized Bone
Vertebrate Fossil Fragment (Calcium Phosphate / Hydroxyapatite)
Chert / Flint
Chert (Cryptocrystalline Quartz, SiO2)
Chert / Flint (with quartz or calcite inclusion)
Silicon dioxide (SiO2)
Pearl
Calcium Carbonate (mostly Aragonite), CaCO3 (with conchiolin)
Chert (Cherty Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Field Pebble)
Microcrystalline / Cryptocrystalline Quartz (SiO2)
Chert (and Limestone)
Chert (consisting of Microcrystalline Quartz, SiO2)
Chert (Jasper/Flint variant)
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified wood (primarily Quartz/Chalcedony, SiO2)
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Flint nodule)
Silicon dioxide (SiO2)
Chert (Flint/Jasper variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (v. Flint)
Sedimentary Cryptocrystalline Quartz (SiO2)
Fossilized Shark Tooth (Fragment)
Elasmobranchii fossil (likely Cretalamna or Squalicorax genus)
Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock exposed to metamorphic heat/pressure; Chemical composition is approximately 86%–98% Carbon)
Amber
Succinite (specifically for Baltic amber); Complex mixture of organic compounds (C10H16O)
Quartz Geode with Calcite/Siderite
Crystalline Silicon Dioxide (SiO2) with Carbonate inclusions
Basalt
Aphanitic Mafic Volcanic Rock
Mica Schist with Iron Staining
Mica Schist
Chert with Weathered Rind (Flint/Chalcedony)
Microcrystalline Quartz (SiO2)
Chert (Yellow Jasper variant)
Microcrystalline Quartz (SiO2)
Banded Chert
Silicon dioxide (SiO2) with impurities
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
Chert (Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline or cryptocrystalline quartz (SiO2)
Chert (often called Flint in this variation)
Silicon dioxide (SiO2) - Microcrystalline quartz
Chert (often called Flint or River Stone)
Microcrystalline Quartz (SiO2)