Limonite (Ironstone)
Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)
Category
Browse sedimentary or igneous (secondary formation) specimens identified by the Rock Identifier community.
Limonite (Ironstone)
Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)
Limonitic Quartzite
Metamorphosed sandstone with Limonite (FeO(OH)·nH2O) staining
Turquoise
Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)
Quartz Druzy Geode
Silicon Dioxide (SiO2) - Crystalline Variety
Black Sand (Magnetite Sand)
Magnetite-rich Placers (Fe3O4)
Gneiss
Gneiss
Gneiss with Quartz Veining
Gneiss (High-grade regional metamorphic rock)
Gneiss
Gneiss
Gneiss
High-grade metamorphic rock (Gneiss)
Leopard Skin Jasper
Rhyolite (Silicon Dioxide with impurities), SiO2
Granite
Granite (composed primarily of Quartz SiO2, Alkali Feldspar KAlSi3O8, and Plagioclase Feldspar)
Gold
Native Gold (Au)
Ammolite
Biogenic gemstone (Aragonite, CaCO3)
Quartzite
Quartzite (SiO2)
Opalite
Opalescent Glass (SiO2 + coloring agents)
Moss Agate
Chalcedony (Silicon Dioxide - SiO2) with inclusions
Jadeite and Mixed Gemstones (Ruby, Sapphire, Emerald)
Jadeite (NaAlSi2O6), Corundum (Al2O3), Beryl (Be3Al2(Si6O18))
Pearl (as a biogenic mineral/gemstone)
Calcium Carbonate (mostly Aragonite), CaCO3
Citrine
Quartz (SiO₂) variety
Sandstone
Quartz Arenite (a common type of sandstone, given the appearance), Arkose, Greywacke (depending on mineralogy)
Puddingstone
Conglomerate (specifically a type of jasper conglomerate or quartz conglomerate)
Green Moss Agate / Jasper
Silicon Dioxide (SiO2) - Microcrystalline Quartz with Iron and Manganese inclusions
Gneiss
Gneissic Metamorphic Rock
Slate
Slate (a fine-grained, foliated metamorphic rock). Mineral composition: Primarily composed of mica minerals (muscovite, chlorite, sericite) and quartz, with minor amounts of hematite, pyrite, and other accessory minerals.
Schist
Mica Schist
Anthracite Coal
Anthracite (a variety of coal, predominantly carbon)
Calcite (likely a tumbled specimen)
Calcite (CaCO 3 )
Quartz Pebble
Silicon Dioxide (SiO2)
Yellow Jasper
Silicon Dioxide (SiO2) with Goethite/Iron oxide impurities
Carnelian
Carnelian (SiO2 - Silicon Dioxide with Iron Oxide impurities)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Quartzite
Quartzite (SiO2)
Wonderstone (Banded Rhyolite)
Rhyolite (Silicon Dioxide with Iron Oxide impurities)
Sandstone
Arenite (a specific type of sandstone with less than 15% matrix)
Quartz (in a rock matrix)
Quartz (SiO2)
Gneiss (Banded Gneiss)
Gneiss
Milky Quartz with Iron Staining
Silicon Dioxide (SiO2)
Pink Dyed Agate
Chalcedony (SiO2) with artificial dyes
Quartz Pebble
Silicon Dioxide (SiO2)
Malachite
Malachite [Cu2CO3(OH)2]
Prehnite
Prehnite, Ca2Al(AlSi3O10)(OH)2
Gold Nugget
Native Gold (Au)