Petrified Wood
Silicified Wood (primarily Quartz/SiO2)
Category
Browse mineral side rock specimens identified by the Rock Identifier community.
Petrified Wood
Silicified Wood (primarily Quartz/SiO2)
Limonite Concretion (Ironstone)
Limonite / Goethite (FeO(OH)·nH2O)
Quartz with Iron Oxide
Silicon Dioxide (SiO2) with Fe2O3 inclusions
Dalmatian Jasper
Peralkaline rhyolite
Gneiss
Gneiss
River Stone (likely Siltstone or fine-grained Sandstone)
Clastic Sedimentary Rock (Lithic Wacke / Siltstone)
Vesicular Basalt
Amygdaloidal Basalt (Mafic extrusive volcanic rock)
Slag
Ferrous Slag (Amorphous calcium-magnesium-aluminum silicates)
Quartz (Iron-Stained or Milky Quartz)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Clear Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Silicon dioxide (SiO2)
Clear Quartz
Quartz (Silicon Dioxide, SiO2)
Quartz (with iron oxide staining)
Silicon Dioxide (SiO2)
Prehnite
Ca2Al(AlSi3O10)(OH)2 (Calcium Aluminum Silicate hydroxide)
Obsidian
Volcanic Glass (SiO2)
Fossilized Oyster Shell
Exogyra or Ostrea (Gryphaeidae/Ostreidae family)
Dendrite (Manganese Oxide Dendrites)
Psilomelane or Pyrolusite on Matrix (typically MnO2)
Dalmatian Jasper
Peralkaline rhyolite with arfvedsonite inclusions
Milky Quartz with Iron Inclusions
Silicon Dioxide (SiO2)
Mahogany Obsidian
Volcanic Glass (predominantly SiO2 with Fe2O3 inclusions)
Gneiss (Banded Gneiss)
Gneiss
Lapis Lazuli
Na8[Al6Si6O24]n(S,Cl,SO4,OH)2
Granite or Porphyritic Igneous Rock (weathered)
Granitoid
Red Sandstone
Arenite (with Iron Oxide / Hematite), Formula: SiO2 (Quartz) + Fe2O3 (Hematite coating)
Amethyst
Amethyst (Silicon Dioxide - SiO2 with iron impurities)
Olivine Basalt
Mafic Volcanic Rock (rich in (Mg, Fe)2SiO4)
Manganese Dendrite on Siltstone
Manganese Oxide (pyrolusite or psilomelane) Dendrites
Sandstone
Arenite (primarily SiO2)
Sandstone
Arenite (composed primarily of SiO2)
Crazy Lace Agate
Chalcedony (SiO2) with microcrystalline quartz
Sandstone (with banding/weathering)
Clastic Sedimentary Rock (primarily SiO2)
Travertine
Travertine (CaCO3 - Calcium Carbonate)
Banded Agate (Onyx variety)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Limestone with Calcite Veins
Calcium Carbonate (CaCO3)
Coarse-grained Quartz with Feldspar inclusions
Crystalline Quartz (SiO2) with Orthoclase/Plagioclase Feldspar inclusions
Nephrite Jade
Nephrite
Red Sandstone
Arenite (with Iron Oxide cement)
Granite
Granite (Felsic intrusive igneous rock)
Pink Granite
Phaneritic Felsic Igneous Rock (composed primarily of K-feldspar, Quartz, and Biotite)
Basalt with Amygdaloidal Inclusions
Aphanitic Mafic Volcanic Rock (Basalt)