Limonite (Iron Ore/Sandstone mixture)
Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix
Category
Browse mineral precipitate (anthropogenic context) specimens identified by the Rock Identifier community.
Limonite (Iron Ore/Sandstone mixture)
Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix
Quartz Geode in Sedimentary Matrix
Silicon Dioxide (SiO2) within a limestone/dolostone host
Bumblebee Jasper (technically a type of Agate/Anhydrite)
Calcite and Anhydrite with inclusions of Realgar and Orpiment (As2S3)
Chert (often called Flint in this context)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Quartzite
Quartzite (primarily SiO2)
Jasper
Jasper (Silicate mineral, SiO2)
Aragonite
Aragonite (CaCO3)
Limonite (Ironstone)
Limonite (FeO(OH)·nH2O)
Ferruginous Quartz
Quartz with Iron Oxide inclusions (SiO2 + Fe2O3)
Carnelian
Carnelian (SiO2 - Silicon Dioxide with Hematite impurities)
Yellow Chalcedony
Silicon Dioxide (SiO2)
Limonite (Iron-rich Siltstone / Sandstone base)
Hydrous ferric oxide mixture (FeO(OH)·nH2O)
Milky Quartz Vein with Matrix
Silicon Dioxide (SiO2)
River Chalcedony / Agate
Chalcedony (Silicon Dioxide, SiO2)
Ocean Jasper
Orbicular Jasper (SiO2)
Carnelian Agate
Carnelian (Silicon Dioxide - SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Hematite
Iron(III) oxide (Fe2O3)
Heulandite with Stilbite
Heulandite-Ca ((Ca,Na)2-3Al3(Al,Si)2Si13O36·12H2O) and Stilbite-Ca (NaCa4(Si27Al9)O72·28H2O)
Chert (often called Flint in this context)
Silicon Dioxide (SiO2)
Druzy Quartz
Silicon Dioxide (SiO2)
Magnetite with Pyrite or Chalcopyrite inclusions
Magnetite (Fe3O4) with Pyrite (FeS2)
Geode (unopened) or Calcareous Nodule
Siliceous or Calcareous Concretion/Nodule
Amethyst Geode
Amethyst (Silicon Dioxide, SiO2)
Amber in Matrix
Succinite (Carbon-based organic polymer)
Quartz (Milky/Crystalline variety)
Silicon Dioxide (SiO2)
Orange Calcite
Calcium Carbonate (CaCO3)
Hematite
Iron(III) oxide (Fe2O3)
Honey Calcite
Calcium Carbonate (CaCO3)
Quartz (Milky/Bull Quartz)
Silicon Dioxide (SiO2)
Carnelian (Chalcedony)
Silicon Dioxide (SiO2)
Limonite (Hydrated Iron Oxide / Bog Iron)
FeO(OH)·nH2O
Carnelian (a variety of Chalcedony)
SiO2 (Silicon Dioxide) primarily colored by iron oxide (Hematite)
Amethyst
Amethyst (Silicon Dioxide - SiO2 with Iron impurities)
Tiger's Eye (often misinterpreted as Gold Ore in this context)
Pseudomorph of Quartz after Crocidolite (SiO2)
Orange Calcite (Polished Sphere)
Calcium Carbonate (CaCO3)
Amethyst (Quartz)
Silicon Dioxide (SiO2) with Iron impurities
Onyx Marble (also commonly called Onyx)
Calcite (CaCO3), often with other mineral impurities
Quartz Vein Rock
Quartz (Silicon Dioxide, SiO2)
Slag (Industrial Glass Slag)
Amorphous Silica / Ferro-silicate Slag
Milky Quartz
Crystalline Silicon Dioxide (SiO2)
Chalcedony (specifically Agate or Flint)
Silicon Dioxide (SiO₂)