Sandstone (Picture Sandstone)
Arenite (primarily SiO2)
sedimentary
Category
Mineral (Silicate Replaced Organic Material)
Browse mineral (silicate replaced organic material) specimens identified by the Rock Identifier community.
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Chert (Flint)
Chert (Silicon Dioxide, SiO2)
sedimentary
Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock transitioned to metamorphic)
metamorphic
Amazonite
Microcline (var. Amazonite) - KAlSi3O8
mineral
Emerald
Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)
mineral
Ferruginous Quartz
Iron-stained Quartz (Silicon Dioxide, SiO2 with Fe2O3 inclusions)
mineral
Chlorastrolite (Greenstone)
Chlorastrolite (variety of Pumpellyite) - Ca2(Mg,Fe)Al2(SiO4)(Si2O7)(OH)2 · H2O
mineral
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
sedimentary
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Green Calcite
Calcium Carbonate (CaCO3)
mineral
Mica Schist
Mica Schist (primarily Muscovite or Biotite sheet silicates)
metamorphic
Quartzite Geode or Crystalline Quartz Node
Silicon Dioxide (SiO2)
metamorphic
Chert (Limestone-based)
Silicon dioxide (SiO2)
sedimentary
Sandstone (Quartzose)
Arenite (composed mainly of SiO2)
sedimentary
Sandstone
Arenite (SiO2 based)
sedimentary
Sandstone
Arenite
sedimentary
Pearl
Aragonite / Calcium Carbonate (CaCO3)
mineral
Limestone with Calcite Veins
Calcium Carbonate (CaCO3)
sedimentary
Chert (Jasper/Flint variety)
Silicon Dioxide (SiO2)
sedimentary
Mica Schist
Mica Schist (predominantly Muscovite or Biotite sheet silicates)
metamorphic
Garnet (likely Almandine or a blend)
Garnet group: X3Y2(SiO4)3, where X can be Ca, Mg, Fe2+, Mn2+ and Y can be Al, Fe3+, Cr3+. Given the dark, somewhat reddish-brown appearance in the image, it's likely Almandine (Fe3Al2(SiO4)3) or a mix with other iron-rich garnets.
Mineral
Septarian Nodule (Dragon Stone)
Septarian concretion (composition: CaCO3 - Calcite, Aragonite, and Siderite/Limestone)
sedimentary
Coprolite
Coprolite (fossilized feces)
sedimentary
Chert (varietal: Flint/Jasper mix)
Hydrous Silica (SiO2)
sedimentary
Banded Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Mookaite Jasper
Silicified Radiolarite (SiO2 with impurities)
sedimentary
Thunderegg (Agetized Geode nodule)
Rhyolitic Agate Nodule (SiO2 filling volcanic cavities)
igneous
Sandstone
Arenite (SiO2 dominant)
sedimentary
Septarian Nodule
Septarian Concretion (CaCO3 + Hydrated SiO2)
sedimentary
Sandstone
Clastic Sedimentary Rock (primarily SiO2)
sedimentary
Fluorite
Calcium Fluoride (CaF2)
mineral
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Chalcedony (Botryoidal or Agate nodule)
Silicon Dioxide (SiO2)
mineral
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Jasper)
Silicon dioxide (SiO2)
sedimentary
Sandstone (Quartzose Sandstone)
Arenite (SiO2)
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Chrysoprase
Chrysoprase (a variety of Chalcedony, SiO₂)
Mineral
Tiger's Eye
Fibrous Quartz (SiO2) with Limonite
mineral
Amber
Succinite (Carbon-based organic compound; approximate formula C10H16O)
Mineraloid
Baltic Amber (Butterscotch or Egg Yolk Variety)
Succinite (chemical formula: C10H16O)
Organic Gemstone (not a rock or mineral)
Natural Pearl (appearing in a jewelry setting)
Calcium Carbonate (mostly Aragonite), CaCO3 with Conchiolin
mineral