Chalcedony on Ironstone
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3/FeOOH)
Category
Browse sedimentary (secondary mineral) within igneous specimens identified by the Rock Identifier community.
Chalcedony on Ironstone
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3/FeOOH)
Septarian Nodule
Septarian Concretion (Calcium Carbonate/Aragonite/Calcite)
Agate Bookend / Quartz Geode
Silicon Dioxide (SiO2)
Olivine (Peridot)
Magnesium Iron Silicate ((Mg, Fe)2SiO4)
Dalmatian Stone
Dalmatian Jasper / Feldspathic Igneous Rock
Diamond (Cut Gemstones in Jewelry)
Carbon (C)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Amethyst Cluster
Silicon Dioxide with Iron impurities (SiO2)
Chert (with potential fossil inclusion)
Microcrystalline Quartz (SiO2)
Chert (Jasper variation)
Silicon dioxide (SiO2)
Sandstone Cobble with Iron Staining
Arenite with Limonite/Hematite staining
Rounded quartz-rich river pebble
Quartz (SiO₂), likely derived from quartzite or granitic rock
Granite Cobble
Phaneritic plutonic rock (dominated by Quartz, Feldspar, and Mica)
Weathered pegmatite or feldspar-rich granite fragment
Granitic pegmatite, composed mainly of potassium feldspar and quartz, with minor mica; exact identification is uncertain from the photograph
Olivine (likely Peridot variety)
Olivine Mineral Group (specifically Forsterite-Fayalite solid solution series); Chemical formula: (Mg,Fe)2SiO4
Granite
Granite (Felsic Plutonic Rock)
Quartz (Milky Quartz)
Quartz (SiO2 - Silicon Dioxide)
Quartz-lined Geode / Chalcedony Nodule
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Ferruginous Quartz
Quartz (Silicon Dioxide, SiO2) with Iron Oxide Inclusions
Smoky Quartz (with Iron Inclusions)
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Chalcedony Agate Geode / Nodule
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Specularite in Quartz
Specular Hematite (Fe2O3) in Quartz (SiO2)
Celestine (or Celestite) on Matrix
Celestine (SrSO4)
Arfvedsonite in Quartz (also known as Eudialyte/Garnet Syenite variety)
Arfvedsonite [Na3(Fe2+)4Fe3+Si8O22(OH)2] within a silicate matrix
Milk Quartz (Common White Quartz)
Quartz (Silicon Dioxide, SiO2)
Chert / Flint
Silicon Dioxide (SiO2)
Quartz (Small Fragment)
Silicon Dioxide (SiO2)
Aquamarine (Tumbled)
Beryl (Be3Al2Si6O18)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Granite with Quartz/Feldspar Vein
Granite
Pyrite
Iron Sulfide (FeS2)
Quartz
Silicon Dioxide (SiO2)
Quartz (Pebble)
Silicon Dioxide (SiO2)
Quartz Crystal Rock
Silicon Dioxide (SiO2)
Yellow Calcite
Calcium Carbonate, CaCO3
Diamond (Faceted)
Carbon (C)
Pink Calcite
Calcium Carbonate (CaCO3)
Prehnite
Ca2Al2Si3O10(OH)2
Tourmalinated quartz sphere
Quartz (SiO₂) with black schorl tourmaline inclusions
Dalmatian Jasper
Peralkaline Rhyolite (composed of Quartz, Feldspar, and Arfvedsonite)