Limonite Concretion
Hydrated Iron Oxide-Hydroxide, FeO(OH)·nH2O
Category
Browse mineraloid (human made geological specimen) specimens identified by the Rock Identifier community.
Limonite Concretion
Hydrated Iron Oxide-Hydroxide, FeO(OH)·nH2O
Epidote
Epidote (Ca2(Al,Fe)3(SiO4)3(OH))
Ferruginous Sandstone (Ironstone)
Sandstone with Hematite/Goethite cement (SiO2 + FeO(OH))
Banded Calcite
Calcium Carbonate (CaCO3)
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
Chert (Jasper variation)
Microcrystalline Quartz (SiO2)
Chert Nodule (Flint)
Silicon Dioxide (SiO2)
Drill Core (Basalt or Andesite)
Volcanic porphyry (mafic to intermediate)
Banded River Stone (Greywacke or Siltstone subtype)
Sedimentary Banded Siltstone
Milky Quartz with inclusions
Silicon Dioxide (SiO2)
Quartz (Water-worn pebble)
Silicon Dioxide (SiO2)
Orange chromium diopside (likely tumbled)
Diopside, CaMgSi₂O₆; orange color may reflect iron-rich composition or surface treatment/inclusion
Pyrite with Iron Oxides (Fool's Gold in Matrix)
Iron Sulfide (FeS2)
Sandstone
Arenite (primarily SiO2)
Pink Granite
Phaneritic Felsic Igneous Rock (composed of orthoclase, quartz, and plagioclase)
Probable weathered basalt or andesite
Fine-grained mafic to intermediate volcanic rock; commonly plagioclase ± pyroxene, amphibole, and iron oxides
Ferruginous Quartz
Silicon Dioxide with Iron Oxide (SiO2 + Fe2O3)
Granite (specifically Pink or Red Granite)
Phaneritic Felsic Igneous Rock (Granite)
Quartz (with probable host rock)
Silicon Dioxide (SiO2)
Porphyry
Porphyritic Igneous Rock
Coquina
Coquina (Bioclastic Limestone)
Quartz (Milky/Crystalline variety)
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Granite Pebble
Granite (Phaneritic intrusive igneous rock comprising Quartz, Feldspar, and Mica)
Chalcedony (Botryoidal/Agate nodule)
Microcrystalline Quartz (SiO2)
Granite
Plutonic felsic rock (Quartz, Feldspar, Mica)
Boxwork Siderite or Sepatarian Nodule Weathering
Siderite (FeCO3) with secondary mineralization or Boxwork Geode fragment
Quartz (likely a weathered/tumbled piece)
Quartz (SiO₂)
Fossiliferous Limestone (Crinoid stem fossils)
Sedimentary Limestone with Crinoidea ossicles
Green Aventurine
Quartz (SiO2) with Fuchsite inclusions
Chert (Jasper variation)
Microcrystalline Quartz (SiO2)
Sandstone Pebble (Quartzite-rich)
Clastic Terrigenous Sedimentary Rock (SiO2 dominant)
Synthetic Costume Glove (Paws)
Polyethylene terephthalate (Polyester) & Polyurethane blend
Chert (Yellow Jasper/Flint pebble)
Microcrystalline Quartz (SiO2)
Quartz (Milky or Clear variety)
Silicon Dioxide (SiO2)
Sandstone (with Iron Staining)
Arenite (composed primarily of SiO2 with Fe2O3 staining)
Sandstone with Iron Staining
Arenite (SiO2 with Fe-oxide coatings)
Petrified Wood
Silicified wood (Quartz/Chalcedony/SiO2)
Galena
Galena (Lead Sulfide), PbS
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Chert
Microcrystalline Quartz (SiO2)
Bivalve Fossil (Shell Fragment)
Class Bivalvia (Calcium Carbonate - CaCO3)