Sandstone concretion (Ironstone-stained)
Arenite with Limonite/Hematite staining (Silica-based with Iron Oxides)
Category
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Sandstone concretion (Ironstone-stained)
Arenite with Limonite/Hematite staining (Silica-based with Iron Oxides)
Sandstone (Stream-rounded)
Arenite (SiO2 based)
Amethyst
Amethyst (a variety of Quartz, SiO2)
Sandstone with Manganese Dendrites/Oxide coatings
Arenite with Pyrolusite and Romanechite (MnO2)
Yellow Jasper
Silicon dioxide (SiO2)
Kidney Stone (Renal Calculus)
Calcium oxalate monohydrate (Whewellite) / CaC2O4·H2O
Fluorite
Calcium Fluoride (CaF2)
Limonite Concretion
Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)
Blue Chalcedony
Silicon Dioxide (SiO2)
Ocherous Sandstone (Ferruginous Sandstone)
Ferruginous Arenite (SiO2 with Fe2O3)
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) within a metamorphic matrix
Diamond
Diamond (C)
Quartzite Cobble
Quartzite (primarily SiO2)
Sandstone (likely Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
Sandstone (Ferruginous)
Arenite (with iron oxide cement, Fe2O3)
Yellow Jasper
Silicon Dioxide (SiO2) with impurities of Iron or Goethite
Fluorite (Purple variety)
Calcium Fluoride (CaF2)
Green Aventurine
Silicon Dioxide (SiO2) with Fuchsite inclusions
Fossiliferous Limestone
Limestone (CaCO3 - Calcium Carbonate)
Limestone (specifically Travertine or Tufa)
Calcium Carbonate (CaCO3)
Quartz Pebble (Chert/Chalcedony)
Silicon Dioxide (SiO2)
Quartz with Mica inclusions (Gold-colored Mica)
Silicon Dioxide (SiO2) with Potassium Aluminum Silicate (Phlogopite/Muscovite) inclusions
Quartzite (Potentially Ferruginous)
Quartzite (SiO2)
Quartzite with Quartz Geode / Vug
Crystalline Silicon Dioxide (SiO2) in Metamorphic Host
Sandstone (Pebble/Cobble)
Arenite (primarily SiO2)
Fluorite
Calcium Fluoride (CaF2)
Zebra Jasper
Tetragonal Silicon Dioxide (Quartz) with impurities
Chalcedony (Common Opal variant or Chert/Flint)
Silicon Dioxide (SiO2)
Agate / Banded Chalcedony
Agate (Silicon Dioxide / SiO2)
Red Quartzite
SiO2 (Silicon Dioxide with iron oxide impurities)
Silver (Native Silver/Alloy Specimen)
Ag (Native Silver element), specifically a 90% Ag / 10% Cu alloy
Chalcedony (Grey/White Agate)
Silicon Dioxide (SiO₂)
Peridot (Olivine)
(Mg,Fe)2SiO4 (Magnesium Iron Silicate)
Amygdaloidal Basalt
Amygdaloidal Basalt (Ca-rich Plagioclase, Pyroxene, and Olivine)
Precious Opal
Hydrated Silica (SiO2·nH2O)
Pyrite
Iron Sulfide (FeS2)
Moonstone
Feldspar (Orthoclase with Albite), (K,Na)AlSi3O8
Yellow Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Ocean Jasper
Orbicular Jasper (Silicon Dioxide, SiO2)
Moss Agate
Moss Agate (a variety of Chalcedony, SiO ₂)
Quartzite pebble
Quartzite (primarily SiO2)
Rough Green Calcite
Calcite (Calcium Carbonate, CaCO3)