Ironstone Concretion (Nutstone)
Ironstone (with High Limonite/Hematite Content)
Category
Browse industrial byproduct (often mistaken for obsidian or mineral) specimens identified by the Rock Identifier community.
Ironstone Concretion (Nutstone)
Ironstone (with High Limonite/Hematite Content)
Sandstone (likely Red/Brown Sandstone)
Arenite (SiO2 based)
Sandstone
Arenite (SiO2 based)
Prehnite
Prehnite (Ca2Al2Si3O10(OH)2)
Green Aventurine in Host Rock
SiO2 (Quartz with Fuchsite inclusions)
Epidote (with Quartz and Feldspar)
Epidote (unakalite/unite), Ca2(Al2Fe3+)(SiO4)(Si2O7)O(OH)
Bornite (Peacock Ore)
Bornite (Cu5FeS4)
Satin Spar (often marketed as Selenite)
Fibrous Gypsum (CaSO4·2H2O)
Sandstone
Arenite
Celestite (Celestine)
Strontium sulfate (SrSO4)
Epidote in Matrix (likely Amphibolite or Gneiss)
Epidote (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH)) in Metamorphic Matrix
Quartz Geode (partially opened)
Silicon Dioxide (SiO2) with iron staining
Orange Calcite
Calcium Carbonate (CaCO3)
Quartz-bearing Ore (likely Gold-bearing Quartz)
Quartz (SiO2) with potential sulfide mineralization (Pyrite/Arsenopyrite)
Quartz Geode
Silicon Dioxide (SiO2)
Citrine or Yellow Quartz
Silicon Dioxide (SiO2) with iron impurities
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Fuchsite (Green Muscovite in Quartz)
Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)
Pyromorphite on Epidote
Pyromorphite [Pb5(PO4)3Cl] and Epidote [Ca2(Al2,Fe3+)(SiO4)3(OH)]
Porphyry (likely Porphyritic Andesite or Basalt)
Porphyritic Igneous Rock
Sandstone
Arenite (primarily SiO2)
Ironstone Concretion (Moqui Marble type)
Ferruginous Concretion (Fe2O3 / FeO(OH))
Bornite (Peacock Ore)
Bornite (Cu5FeS4)
Limonite (with Pyrite)
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
Orca Agate (Blue Chalcedony)
Silicon Dioxide (SiO2)
Eudialyte in Matrix
Na15Ca6(Fe,Mn)3Zr3(Si,Nb) (Si25O73) (OH,Cl,H2O)3
Fluorite and Rose Quartz
Fluorite (CaF2), Rose Quartz (SiO2)
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Ferruginous Sandstone
Sandstone with Iron Oxide (Limonite/Goethite)
Red Sandstone
Arenite (Ferruginous Sandstone)
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
Yellow Calcite
Calcium Carbonate (CaCO3)
Azurite and Malachite
Azurite (Cu3(CO3)2(OH)2) and Malachite (Cu2(CO3)(OH)2)
Black Marble
Recrystallized Calcite (CaCO3)
Green Sandstone (Glauconitic Sandstone)
Glauconitic Sandstone (K(Fe,Al)2(Si,Al)4O10(OH)2)
Dendritic Quartz
Silicon Dioxide with inclusions (SiO2)
Pyrite in Quartz (Drill Core)
Silicon Dioxide (SiO2) with Iron Sulfide (FeS2) inclusions
Almandine Garnet in Matrix
Almandine (Fe3Al2(SiO4)3)
Limonite (Iron Ore/Hydrated Iron Oxide)
Limonite (mixture of FeO(OH)·nH₂O minerals, mainly Goethite, FeO(OH) and Lepidocrocite, FeO(OH))
Fossilized Bone Fragment
Permineralized Vertebrate Fossil (Hydroxyapatite replaced by Minerals)
Granitic Gneiss
Gneiss (Metamorphic rock of granitic composition)
Kidney Stone (Renal Calculus)
Calcium oxalate monohydrate (Whewellite) / CaC2O4·H2O