Agate Geode
Cryptocrystalline Quartz (SiO2)
Category
Browse mineral precipitate (anthropogenic context) specimens identified by the Rock Identifier community.
Agate Geode
Cryptocrystalline Quartz (SiO2)
Yellow Calcite
Calcium Carbonate (CaCO3)
Banded Agate (Lace Agate)
Agate (Variety of Cryptocrystalline Quartz), SiO2
Quartz
Silicon Dioxide (SiO2)
Septarian Nodule (Micro-fragment)
Septarian Nodule / Concretion (CaCO3 + CaMg(CO3)2 + Quartz)
Quartz (likely Clear Quartz or Rock Crystal)
Quartz (SiO2)
Quartz Geode
Silicon Dioxide (SiO2)
Quartz Geode
Quartz (Silicon Dioxide, SiO2)
Quartz Geode
Silicon Dioxide (SiO2) in a Secondary Sedimentary/Volcanic cavity
Quartz Geode
Silicon Dioxide (SiO2)
Quartz Geode
Silicon Dioxide (SiO2)
Amethyst Geode Cathedral
Amethyst (Silicon Dioxide - SiO2 with Iron impurities)
Amygdaloidal Basalt
Vesicular Basalt with secondary mineral infilling (commonly Zeolite, Calcite, or Quartz)
Yellow Calcite
Calcite (Calcium Carbonate, CaCO3)
Agate Geode
Cryptocrystalline Quartz (SiO2)
Specularite (Specular Hematite)
Iron Oxide (Fe2O3)
Yellow Agate
Silicon Dioxide (SiO2)
Dolomite on Prehnite (Saddle-shaped Dolomite)
Dolomite [CaMg(CO3)2] on Prehnite [Ca2Al(AlSi3O10)(OH)2]
Quartz (likely Milky Quartz or Chalcedony)
Quartz (SiO2 - Silicon Dioxide)
Calcite
Calcite (Mineral, Calcium Carbonate - CaCO3)
Agate
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Quartz with Iron Stains
Quartz (SiO2) with iron oxide/hydroxide staining
Calcite
Calcite (CaCO₃, Calcium Carbonate)
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 Vein in Sandstone
Hydrothermal Quartz (SiO2) in Arenite
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)
Oolite (Ooid Limestone)
Ooidal Limestone (comprised of CaCO3)
Limonite (Bog Iron)
Limonite (Hydrated iron(III) oxide-hydroxide) - FeO(OH)·nH2O
Yellow Jasper / Chert
Silicon Dioxide (SiO2) with Goethite or Limonite inclusions
Precious Opal in Matrix
Hydrated Silica (SiO2·nH2O)
Orange Calcite
Calcium Carbonate (CaCO3)
Aragonite (Onyx Marble)
Calcium Carbonate (CaCO3), Orthorhombic crystal system
Banded Agate (specifically Gobi Eyes or Eye Agate)
Silicon Dioxide (SiO2) - Variety of Chalcedony
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Milky Quartz
Silicon Dioxide (SiO2)