Amethyst (Chevron or Banded Amethyst)
Silicon Dioxide (SiO2) with iron impurities
Category
Browse sedimentary rock (specifically a concretion or possibly a geode) specimens identified by the Rock Identifier community.
Amethyst (Chevron or Banded Amethyst)
Silicon Dioxide (SiO2) with iron impurities
Sandstone (likely a river or beach pebble)
Sandstone (a clastic sedimentary rock)
Exposed Aggregate Concrete (Pea Gravel)
Concrete with Siliceous Alluvial Gravels
Chalcedony (Common Opal variant)
Silicon dioxide (SiO2) with varying levels of hydration
Basalt River Stone
Basalt (Mafic volcanic rock, primarily Plagioclase and Pyroxene)
Orange Calcite
Calcium Carbonate (CaCO3)
Leopard Skin Jasper
Silicon Dioxide (SiO2) with various inclusions
Yellow Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Amethyst
Silicon Dioxide with Iron impurities (SiO2)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Gneiss (with Quartz and Biotite Mica)
Gneiss
Ferruginous Conglomerate
Conglomerate with Iron-Oxide Matrix (SiO2 + Fe2O3/FeO(OH))
Milky Quartz
Silicon Dioxide (SiO₂)
Garnet (specifically Almandine)
Almandine - Fe3Al2(SiO4)3
Chert (often called Flint)
Chert (Cryptocrystalline Quartz, SiO2)
Yellow Jasper
Jasper (Silicon Dioxide, SiO2)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Pink Granite
Phaneritic Felsic Igneous Plutonic Rock
Amethyst
Amethyst (Silicon Dioxide, SiO2 with Iron impurities)
Amethyst with Marcasite accents
Amethyst (Silicon Dioxide SiO2) and Marcasite (Iron Sulfide FeS2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Chalcedony (Botryoidal)
Silicon Dioxide (SiO2)
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Yellow Jasper
Silicon Dioxide (SiO2) with Goethite/Iron oxide inclusions
Chert (Jasper variety)
Chert (SiO2)
Yellow Jasper / Chert
Silicon Dioxide (SiO2) with Goethite or Limonite inclusions
Spinosaurus Tooth Fossil
Spinosaurus aegyptiacus (Calcium Phosphate/Apatite)
Yellow Jasper
Tectosilicates (SiO2) with Goethite/Iron oxide inclusions
Citrine Quartz
Quartz (SiO2) - specifically, a variety of macrocrystalline quartz
Chalcedony (Common Opal variant)
Silicon dioxide (SiO2) with microcrystalline structure
Pink Granite
Granite (Phaneritic felsic intrusive igneous rock)
Banded Chert (Flint)
Cryptocrystalline Quartz (SiO2)
Mammoth Tooth Fragment
Mammuthus primigenius (fossilized dentin and enamel)
Chert (often called Flint or Jasper depending on color)
Chert (SiO2 - Microcrystalline or Cryptocrystalline Quartz)
Quartz Geode (Water-worn)
Silicon Dioxide (SiO2)
Barite
Barium Sulfate (BaSO4)
Chert
Chert (SiO2)
Yellow Jasper
Cryptocrystalline Quartz (SiO2) with iron inclusions
Chert (Jasper)
Silicon Dioxide (SiO2)
Pyrite
Iron Sulfide (FeS2)
Satin Spar (often marketed as Selenite)
Fibrous Gypsum (CaSO4·2H2O)
Yellow Jasper
Silicon Dioxide (SiO2) with iron hydroxides (Goethite/Limonite)