Limonite on Sandstone
Iron Oxyhydroxide (FeO(OH)·nH2O) on Quartz Sandstone
Category
Browse mineral specimens identified by the Rock Identifier community.
Limonite on Sandstone
Iron Oxyhydroxide (FeO(OH)·nH2O) on Quartz Sandstone
Greenstone / altered basalt (probable)
Chlorite–epidote–actinolite aggregate; commonly metabasalt (greenstone)
Carved serpentine wing sculpture
Serpentine-group rock, chiefly antigorite/lizardite: Mg3Si2O5(OH)4
Green Fluorite
Fluorite (Calcium Fluoride, CaF2)
Limonite (Iron Ore)
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
Limonite Boxwork / Iron Ore Concretion
FeO(OH)qnH2O (Hydrated iron oxide)
Botryoidal Goethite
Goethite (α-Fe3+O(OH))
Quartz Pebble
Silicon Dioxide (SiO2)
Limonite Concretion
Goethite/Limonite concretion (FeO(OH)·nH2O)
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Biotite-rich gneiss (probable)
Foliated quartz–feldspar–biotite gneiss; composition commonly includes quartz (SiO₂), feldspar, and biotite mica
Quartz Pebble
Silicon Dioxide (SiO2)
Limonite Geode / Ironstone Concretion
Hydrated iron oxide-hydroxide (FeO(OH)·n H2O)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Fossilized Shark Tooth (Megalodon or Carcharocles species fragment)
Otodus megalodon / Carcharocles spp. (Apatite / Calcium Phosphate)
Fossilized Shark Tooth
Chondrichthyes (class)
Polished orbicular jasper (likely ocean jasper)
Silicified volcanic rock; microcrystalline quartz/chalcedony (SiO₂) with iron oxides and altered volcanic minerals
Limonite (Iron Ore/Bog Iron)
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
Polished serpentine breccia
Serpentinite, commonly serpentine-group minerals with carbonate and magnetite
Tumbled reddish-brown mineral or gemstone fragment
Indeterminate from image; possibly carnelian (microcrystalline quartz), jasper, or garnet
Mixed Mineral and Fossil Collection
Multi-specimen assemblage (SiO2, CaCO3, FeS2, etc.)
Limonite (Iron Ore)
FeO(OH)·nH2O
Unidentified metallic-looking mineral fragment
Indeterminate; possible galena, magnetite, or metal-rich sulfide/ore fragment
Uncertain polished mineral specimen
Indeterminate; possibly quartz or feldspar with iron-oxide staining
Unidentified small mineral fragments
Likely quartz- or feldspar-rich material; species cannot be determined reliably from the image
Quartz with Pyrite
Silicon Dioxide (SiO2) with Iron Sulfide (FeS2)
Chrysocolla
Hydrated copper silicate - Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O
Granite
Granite (composed primarily of Quartz, Potassium Feldspar, Plagioclase, and Biotite/Amphibole)
Gneiss
Gneiss
Gneiss
Gneiss (High-grade Metamorphic Rock)
Gneiss
Gneiss (High-grade metamorphic rock)
Gneiss
Gneiss
Granite Pebble (Weathered)
Phaneritic Felsic Igneous Rock
Banded Gneiss
Gneiss (Metamorphic Rock)
Diorite
Diorite
Quartz pebble
Silicon dioxide (SiO2)
Granite
Intrusive Igneous Rock
Granite
Intrusive Igneous Rock
Conglomerate / Breccia Matrix (Aggregated Rock)
Sedimentary Breccia / Conglomerate
Gneiss (Banded Gneiss Cobble)
Gneiss