Basalt (tumbled/river-worn)
Mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
Category
Browse sedimentary (secondary mineral) within igneous specimens identified by the Rock Identifier community.
Basalt (tumbled/river-worn)
Mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
Hematite
Iron(III) oxide (Fe2O3)
Chalcedony (Grey/White Agate)
Silicon Dioxide (SiO₂)
Pyrite (on Quartz matrix)
Iron Disulfide (FeS2)
Blue Calcite
Calcium Carbonate (CaCO3)
Pyrite
Iron Sulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Fluorite (Green Fluorite)
Calcium Fluoride (CaF2)
Quartz Druzy Geode
Silicon Dioxide (SiO2) - Crystalline Variety
Quartz Geode
Silicon Dioxide (SiO2) within a geode
Chert (Yellow Jasper)
Silicon Dioxide (SiO2)
Chert (varieties include Flint or Jasper)
Chert (cryptocrystalline quartz; SiO₂)
White Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Quartz
Silicon Dioxide (SiO2)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Ironstone Concretion (Limonite/Goethite)
Goethite-rich Concretion (FeO(OH))
Milky Quartz (with trace inclusions)
Silicon Dioxide (SiO2)
Spinosaurus fossil (permineralized bone)
Spinosaurus aegyptiacus (Calcium phosphate mineralized with silica/sediment)
Chert (potentially Flint or Mudstone)
Microcrystalline Quartz (SiO2)
Garnet Schist
Almandine Garnet Schist
Magnetite
Magnetite (Fe3O4)
Moonstone
Orthoclase Feldspar (KAlSi3O8) or Albite mixtures
River Chalcedony / Agate
Chalcedony (Silicon Dioxide, SiO2)
Ferruginous Quartz
Silicon Dioxide (SiO2) with iron oxide inclusions
Agate (Chalcedony)
Cryptocrystalline Silica or Silicon Dioxide (SiO2)
Agate
Agate (Silicon Dioxide - SiO2)
Chert (often called Flint when in chalk or limestone)
Silicon Dioxide (SiO₂)
Chert (Jasper variety)
Microcrystalline Quartz (SiO2)
Granitic Gneiss
Gneiss (containing Potassium Feldspar and Quartz)
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions (SiO2)
Chert / River Jasper
Microcrystalline Quartz (SiO2)
Turquoise and Hematite
Turquoise (CuAl6(PO4)4(OH)8·4H2O) and Hematite (Fe2O3)
Green Aventurine
Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)
Yellow Quartz (Citrine-colored Quartz Pebble)
Silicon Dioxide (SiO2)
Labradorite
Labradorite ((Ca, Na)(Al, Si)4O8)
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of Titanium, Iron, or Manganese
Quartz
Quartz (SiO2)
Pyrite
Iron Sulfide (FeS2)
Pyrite
Iron Disulfide (FeS2)