Garnet (Almandine)
Almandine (Fe3Al2(SiO4)3)
Category
Browse sedimentary and metamorphic minerals specimens identified by the Rock Identifier community.
Garnet (Almandine)
Almandine (Fe3Al2(SiO4)3)
Ferruginous Quartz on Ironstone
Silicon Dioxide (SiO2) with Hematite (Fe2O3)
Orange Calcite
Calcium Carbonate (CaCO3)
Fossilized Brachiopod
Phylum Brachiopoda (replaced by Calcite/CaCO3)
Petrified Wood
Silicified wood (Quartz/Chalcedony/Opal replacing organic matter)
Sandstone
Arenite
Ironstone Concretion (Moqui Marble)
Hematite/Goethite Concretion (Fe2O3 / FeO(OH))
Fossilized Coral
Cnidaria (Anthozoa), often replaced by Calcium Carbonate (CaCO3) or Silica (SiO2)
Mica Schist
Schist (Muscovite/Biotite Schist)
Chert / Chalcedony
Silicon Dioxide (SiO2)
Petrified Wood
Silicified wood (Quartz variant, SiO2)
Limonite-stained Chert
Silicon Dioxide (SiO2) with Hydrated Iron Oxide (FeO(OH)·nH2O)
Ironstone Concretion / Goethite Nodules
Ironstone (composed primarily of Goethite FeO(OH) and Limonite)
Petrified Wood
Silicified Wood (SiO2)
Quartz (chalcedony variety) or Limestone with Quartz Veins
SiO2 (for Quartz/Chalcedony); CaCO3 (for Limestone)
Quartz (Common Quartz Pebble)
Silicon Dioxide (SiO2)
Sandstone (with Limonite staining)
Arenite (primarily SiO2 with FeO(OH)·nH2O)
Citrine Quartz
Crystalline Silicon Dioxide (SiO2) with Ferric Iron impurities
Included Quartz Beads (likely Phantom Quartz or Garden Quartz)
Quartz (SiO2) with various mineral inclusions
Satin Spar Selenite
Gypsum (Calcium Sulfate Dihydrate, CaSO4·2H2O)
Aventurine (likely Green Aventurine)
Aventurine (a variety of quartz, SiO₂, with common inclusions of fuchsite)
Shungite
Non-crystalline carbon (high-carbon metamorphic rock)
Almandine Garnet
Iron aluminum silicate - Fe3Al2(SiO4)3
Quartz Pebble
Silicon Dioxide (SiO2)
Sandstone
Arenite (primarily SiO2)
Limonite (Ironstone)
Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)
Quartz
Silicon Dioxide (SiO₂)
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.
Banded Iron Formation (BIF)
Banded Iron Formation
Nephrite Jade
Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)
Ferruginous Sandstone
Sandstone with Iron Oxide (Limonite/Goethite)
Anthracite Coal
Anthracite (Carbon-rich metamorphic sedimentary rock)
Sandstone (Ferruginous)
Arenite with Iron Oxides
Sandstone (Ferruginous)
Arenite with Iron oxide staining (SiO2 with Fe2O3)
Chert (Jasper/Carnelian variety)
Microcrystalline Quartz (SiO2)
Fossilized Coral (Petoskey Stone / Favosites)
Favosites (extinct genus of tabulate coral)
Petrified Wood
Silicified Wood (primarily SiO2)
Chert (often called Flint)
Microcrystalline to cryptocrystalline quartz (SiO2)
Native Sulfur
Sulfur (S)
Hematite
Iron(III) oxide (Fe2O3)
Jasper with Quartz Vein
Silicon Dioxide (SiO2) with impurities
Limonite (Iron Stone/Gossen)
Limonite (FeO(OH)·nH2O)