Pyrite in Shale
Iron Sulfide (FeS2) in Argillaceous Shale
sedimentary
Category
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Browse this image does not display a rock, mineral, or geological specimen. it shows a human hand wearing a ring. specimens identified by the Rock Identifier community.
Emerald and Diamond (Jewelry Setting)
Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities) and Carbon (C)
mineral
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 cementation)
sedimentary
Agate (Chert/Chalcedony)
Silicon Dioxide (SiO2)
mineral
Ironstone Concretion
Siderite or Hematite Concretion
sedimentary
Sandstone
Arenite (SiO2 based)
sedimentary
Petrified Wood
Silicified Wood / Chalcedony (SiO2)
mineral
One Pound Coin (UK)
Nickel-Brass Alloy (Cu-Zn-Ni)
mineral
Gypsum (Wallboard/Drywall)
Calcium Sulfate Dihydrate (CaSO4·2H2O)
sedimentary
Shell Cameo (Sardonyx Shell)
Cassis madagascariensis (Sardonyx shell)
mineral (biogenic silica/calcium carbonate substrate)
Serpentinite (Serpentine Rock)
Primarily composed of serpentine group minerals, such as antigorite, chrysotile, and lizardite. Chemical formula for serpentine minerals is (Mg,Fe)3Si2O5(OH)4.
Metamorphic
Red Jasper
Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions
sedimentary
Sandstone (likely Fossilized Wood or Concrete Simulacrum)
Arenite / Silicified Wood / Anthropogenic Concrete
sedimentary
Optical Calcite (Iceland Spar)
Calcium Carbonate (CaCO3)
mineral
Amethyst
SiO2 (Silicon Dioxide)
Mineral
Quartz Geode
Quartz (Silicon Dioxide, SiO2) Geode
sedimentary
Quartz (Milky/Common variety)
Silicon Dioxide (SiO2)
mineral
Rhodonite
Manganese Silicate (Mn,Fe,Mg,Ca)SiO3
mineral
Cloudy Quartz / Quartz Tumble
Silicon Dioxide (SiO2)
mineral
Sandstone (with potential Quartzite characteristics)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Jasper (likely Brecciated or Multi-colored)
Jasper (SiO2)
sedimentary
Jasper (Petrified Wood variant)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Carnelian
Carnelian (a variety of Chalcedony, SiO₂)
Mineral
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
sedimentary
Black Jasper
Silicon Dioxide (SiO2) with Carbonaceous inclusions
sedimentary
Banded Chert (Agate-like Flint)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Sunstone
Plagioclase Feldspar (Na,Ca)(Al,Si)4O8
mineral
Clay (as a rock-forming material)
Clay minerals (e.g., Kaolinite group, Smectite group, Illite group, Chlorite group)
Mineral
Amethyst
Amethyst (Silicon Dioxide, SiO2)
mineral
River Quartz (Milky and Smoky mix)
Silicon Dioxide (SiO2)
mineral
Carnelian
Carnelian (a variety of Chalcedony, which is a microcrystalline quartz, SiO2)
Mineral (variety of Chalcedony)
Clear Quartz Crystal
Silicon Dioxide (SiO2)
mineral
Druzy Quartz on Chalcedony Matrix
Silicon Dioxide (SiO2)
mineral
Granite
Phaneritic Plutonic Felsic Rock
igneous
Yellow Ochre / Limonite
Limonite (FeO(OH)·nH2O)
Mineral
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide, SiO2)
mineral
Amethyst (Druzy Cluster)
Amethyst (Silicon Dioxide with Iron impurities), SiO2
mineral
Petrified Wood
Silicified Wood (primarily SiO₂ - Silicon Dioxide)
metamorphic
Moonstone (specifically Cat's Eye or Gray Moonstone)
Orthoclase (Potassium Aluminum Silicate) with the formula (K,Na)AlSi3O8
mineral
Tourmaline
Complex Borosilicate - Na(Li,Al)3Al6(BO3)3Si6O18(OH)4 (Elbaite species)
mineral
White Quartz Pebble (with possible Quartz Geode cavity)
Silicon Dioxide (SiO2)
mineral