Biotite (Mica)
K(Mg,Fe)3AlSi3O10(OH,F)2
Category
Browse organic material (likely a fruit or berry) specimens identified by the Rock Identifier community.
Biotite (Mica)
K(Mg,Fe)3AlSi3O10(OH,F)2
Stromatolite (Fossiliferous Limestone)
Biogenic Limestone (Calcium Carbonate, CaCO3)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Sandstone
Arenite (SiO2 principal)
Coarse-grained Granite (Quartz and Feldspar dominated)
Granitoid (KAlSi3O8 – NaAlSi3O3 – CaAl2Si2O8 – SiO2)
Banded Gneiss
Gneiss (Metamorphic Rock)
Quartz (specifically Milky Quartz/Quartzite)
Silicon Dioxide (SiO2)
Sandstone (likely Arkosic)
Clastic Sedimentary Rock
Sandstone (Ferruginous)
Arenite (with Iron Oxide)
Sandstone
Arenite (SiO2 based)
Moss Agate
Chalcedony (Silicon Dioxide) with dendritic inclusions (SiO2)
Sandstone
Arenite (SiO2 based)
Chert (Jasper variety) with Iron Oxide staining
Cryptocrystalline Quartz (SiO2) with Goethite/Limonite impurities
Bituminous Coal
Organic sedimentary rock (humic coal)
Concrete
Hydrated Portland Cement Aggregate Composite
Shale
Laminated Mudstone
Fire Opal (in Matrix)
Hydrated Silica (SiO2·nH2O)
Geode with Quartz/Chalcedony
Silicon Dioxide (SiO2)
Concrete / Anthropogenic Conglomerate
Man-made composite material (Portland cement, aggregate, and water)
Peridot (Olivine)
Olivine ((Mg, Fe)2SiO4)
Aventurine (likely Green Aventurine)
Quartz (SiO2) with included minerals (Fuchsite or Chlorite for green color)
Sandstone
Arenite (primarily SiO2)
Aventurine (likely Green Aventurine)
Silicon Dioxide (SiO2) with included minerals (Fuchsite for green)
Green Sandstone
Glauconitic Sandstone
Chert (Banded)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Silicon Dioxide (SiO2)
Chert Nodule
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
Chert (specifically a fragment with Desert Varnish)
Microcrystalline quartz (SiO2)
Sandstone
Arenite (SiO2 with various cementing agents)
Clay Brick
Ceramic structural unit (Al2O3·2SiO2·2H2O as precursor)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Quartz
Silicon Dioxide (SiO2)
Barite
Barium Sulfate (BaSO4)
Coquina
Bioclastic Limestone
Chert (specifically White Chert or Novaculite)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Chert (or Flint)
Mocrocrystalline Quartz (SiO2)
Chert (Flint)
Chert (Silicon Dioxide, SiO2)
Fancy Jasper
Silicon dioxide (SiO2)
Amber
Succinite (Resinite)
Jasper (likely Lake Superior Jasper)
Jasper (Silicon Dioxide, SiO2)
Rose Quartz (likely carved)
Rose Quartz (SiO2)