Chalcedony
Chalcedony (a microcrystalline variety of Quartz, SiO2)
Category
Browse mineral precipitate (anthropogenic context) specimens identified by the Rock Identifier community.
Chalcedony
Chalcedony (a microcrystalline variety of Quartz, SiO2)
Blue Calcite
Calcium Carbonate (CaCO3)
Ferruginous Sandstone
Arenite with Iron-oxide cement (composed of Quartz and Limonite/Hematite)
Ocean Jasper (Orbicular Jasper)
Silicon Dioxide (SiO2) with various inclusions
Ferruginous Sandstone (Gozzan/Ironstone)
Arenite with Limonite/Goethite cement (FeO(OH)·nH2O)
Slag Glass (Cullet)
Amorphous Silicon Dioxide (SiO2) with metal oxide colorants
Quartz (Milky/Clear)
Silicon Dioxide (SiO2)
Amethyst (Druze)
Silicon Dioxide (SiO2) with iron impurities
Quartz Geode (Cracked Open)
Quartz (Silicon Dioxide - SiO2)
Orange Calcite
Calcite (Calcium Carbonate, CaCO3)
Yellow Calcite
Calcium Carbonate (CaCO3)
Orange Calcite
Calcium Carbonate (CaCO3)
Yellow Calcite
Calcium Carbonate (CaCO3)
Banded Agate (Lace Agate)
Agate (Variety of Cryptocrystalline Quartz), SiO2
Quartz (likely Clear Quartz or Rock Crystal)
Quartz (SiO2)
Chert (Nodule)
Silicon dioxide (SiO2) - Cryptocrystalline Quartz
Amygdaloidal Basalt
Vesicular Basalt with secondary mineral infilling (commonly Zeolite, Calcite, or Quartz)
Agate
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Oolite (Ooid Limestone)
Ooidal Limestone (comprised of CaCO3)
Sandstone (with Liesegang rings or Oxidation)
Arenite (primarily Quartz SiO2 with Iron Oxide Fe2O3 staining)
Sandstone (Ferruginous)
Arenite (composed primarily of SiO2 with Fe2O3 cement)
Septarian Nodule (Dragon Stone)
Septarian concretion (composition: Calcium Carbonate / Calcite, Aragonite, and Limestone/Clay)
Yellow Calcite
Calcite (Calcium Carbonate, CaCO3)
Agate Geode
Cryptocrystalline Quartz (SiO2)
Specularite (Specular Hematite)
Iron Oxide (Fe2O3)
Dolomite on Prehnite (Saddle-shaped Dolomite)
Dolomite [CaMg(CO3)2] on Prehnite [Ca2Al(AlSi3O10)(OH)2]
Calcite
Calcite (CaCO₃, Calcium Carbonate)
Quartz with Iron Stains
Quartz (SiO2) with iron oxide/hydroxide staining
Quartz Geode
Silicon Dioxide (SiO2)
Quartz Geode
Quartz (Silicon Dioxide, SiO2)
Quartz Geode
Silicon Dioxide (SiO2) in a Secondary Sedimentary/Volcanic cavity
Amethyst Geode Cathedral
Amethyst (Silicon Dioxide - SiO2 with Iron impurities)
Quartz Geode
Silicon Dioxide (SiO2)
Septarian Nodule (Dragon Stone)
Septarian Concretion (CaCO3 + CaMg(CO3)2 + SiO2)
Ironstone Concretion (Limonite/Goethite)
Goethite-rich Concretion (FeO(OH))
Moqui Marble (Ironstone Concretion)
Goethite/Hematite Concretion (Fe2O3 / FeO(OH))
Chert Pebble with Quartz Veining
Microcrystalline Quartz (SiO2)
Ferruginous Breccia
Breccia with Iron-rich (Hematite/Goethite) Matrix
Ferruginous Sandstone
Arenite with Iron-Oxide cement (Fe2O3 · nH2O)
Quartz
Silicon Dioxide (SiO2)
Banded Iron Formation (BIF)
Banded Iron Formation with Hematite and Jasper
Limonite (Bog Iron)
Limonite (Hydrated iron(III) oxide-hydroxide) - FeO(OH)·nH2O