Sandstone
Arenite (primarily SiO2)
Category
Browse organic gemstone (not a rock) specimens identified by the Rock Identifier community.
Sandstone
Arenite (primarily SiO2)
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Basalt
Basalt (predominantly Plagioclase Feldspar and Pyroxene)
Limonite Concretion (Ironstone)
Limonite (Hydrated Iron(III) Oxide-Hydroxide, FeO(OH)·nH2O)
Tree Agate
Silicon Dioxide (SiO2) with dendritic inclusions
Amethyst
Amethyst (Silicon Dioxide, SiO2)
Carnelian
Carnelian (SiO2)
Fossiliferous Limestone
Bioclastic Limestone (composition: CaCO3)
Amethyst (Tumbled)
Quartz (Silicon Dioxide, SiO2) with iron impurities
Amethyst (Tumbled)
Amethyst (Silicon Dioxide with Iron impurities) - SiO2
Chert (specifically Flint or Jasper variant)
Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)
Concrete Paver (Artificial Cementitious Rock)
Hydrated Portland Cement Aggregate
Granite
Granite (High-silica plutonic rock)
Sandstone (Quartzose Sandstone)
Clastic Terrigenous Sedimentary Rock (primarily SiO2)
Basalt
Mafic volcanic rock (Primary minerals: Plagioclase feldspar, Pyroxene)
Carnelian (Chalcedony)
Silicon Dioxide (SiO2)
Yellow Ochre / Limonite
Limonite (FeO(OH)·nH2O)
Limestone (specifically fossiliferous/skeletal limestone)
Calcium Carbonate (CaCO3)
Banded Agate (Crazy Lace/Mexican Agate Variety)
Silicon Dioxide (SiO2)
Orange Tabby (Felis catus)
Felis silvestris catus (variety: Red Mackerel Tabby)
Carnelian
Carnelian (SiO2 - Chalcedony colored by Iron Oxide)
Shale
Mudstone/Shale
Topaz
Topaz (Al2SiO4(F,OH)2)
Red Jasper
Silicon dioxide (SiO2) with iron oxide inclusions
Greenschist
Greenschist (Chlorite Schist)
Massive Cryptocrystalline Quartz (Chert/Chalcedony Pebble)
Silicon Dioxide (SiO2)
Carnelian
Carnelian (a variety of Chalcedony, SiO2)
Carnelian Agate
Carnelian (Silicon Dioxide - SiO2)
Carnelian Agate
Silicon Dioxide (SiO2) with high Iron Oxide impurities
Pyrite
Iron Sulfide (FeS2)
Amethyst
Amethyst (SiO2 with Iron impurities)
Amethyst (Polished Cabochon)
Silicon Dioxide (SiO2) with iron impurities
Chalcedony (Agate/Quartz variety)
Cryptocrystalline Quartz (SiO2)
Chert (Pink Jasper variant)
Microcrystalline Quartz (SiO2)
Labradorite
(Ca, Na)(Al, Si)4O8
Greenschist / Greenstone
Greenschist facies metabasite
Red Sandstone
Arenite (primarily Quartz with Hematite cement)
Ocean Jasper
Orbicular Jasper (Silicon Dioxide, SiO2)
Quartzite
Quartzite (primarily Silicon Dioxide, SiO2)
Granite Gneiss
Gneiss (high-grade metamorphic rock)
Sandstone (Ferruginous)
Arenite (variable SiO2 with Fe2O3 staining)
Citrine
Silicon Dioxide (SiO2)