Not A Geological Specimen

Rose Quartz

Silicon Dioxide (SiO2) with trace impurities of Ti, Mn, or Fe

Heat-Treated Citrine (Amethyst)

Silicon Dioxide (SiO2) with iron impurities

Fossilized Horn Coral

Order Rugosa (Rugose Coral)

Libyan Desert Glass

Libyan Desert Glass (SiO2 with trace elements)

Ammonite Fossil

Ammonoidea (typically preserved as Calcite CaCO3 or Pyrite FeS2)

Basalt with Limonite stains

Extrusive mafic igneous rock; Limonite (FeO(OH)·nH2O)

Wishing Stone with Quartz Veins

Quartzite or Quartz-veined Metamorphic Rock (composed mainly of SiO2)

Ironstone Concretion (Moqui Marble)

Iron Oxide Concretion (Fe2O3 / FeO(OH) mixed with SiO2)

Limonite-pseudomorph after Pyrite (Prophecy Stone)

Goethite and Limonite secondary minerals (FeO(OH)·nH2O) replacing Pyrite (FeS2)

Sandstone (lithic/greywacke variant)

Clastic sedimentary rock (primarily SiO2 with rock fragments)

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Basalt (Water-worn pebble)

Mafic Igneous Rock (primarily Plagioclase feldspar and Pyroxene)

Granite or Pegmatite with Mica

Granitoid

Jasper

Silicon dioxide (SiO2)

Geode (unopened) or Calcareous Nodule

Siliceous or Calcareous Concretion/Nodule

Jasper

Jasper (Silicon Dioxide, SiO2)

Quartz (Iron-stained or Ferruginous Quartz)

Silicon Dioxide (SiO2)

Muscovite Schist with Quartz

Mica Schist (KAl2(AlSi3O10)(OH)2)

Amethyst (Raw Quartz)

Silicon Dioxide (SiO2) with iron impurities

Sandstone

Arenite (primarily SiO2)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Amazonite with Smoky Quartz and Feldspar

Microcline (KAlSi3O8) with Quartz (SiO2)

Pyrite in Quartz

Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)

Smoky Quartz (Ferruginous Quartz)

Quartz (Silicon Dioxide, SiO2)

Purple Dyed Agate Geode (Banded Chalcedony)

Silicon Dioxide (SiO2) - variety: Agate

Quartz / Common Opal Transition

Silicon Dioxide (SiO2)

Fossilized Shark Tooth (Fragment)

Elasmobranchii fossil (likely Cretalamna or Squalicorax genus)

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

River Quartzite Pebble

Quartzite (SiO2)

Corundum (Sapphire/Ruby in Matrix)

Corundum (Al2O3)

Jasper

Silicon dioxide (SiO2) with impurities

Muscovite Mica (in Quartz matrix)

Potassium aluminum silicate hydroxide fluoride (KAl2(AlSi3O10)(F,OH)2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

White Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Granite Pebble

Granite (Phaneritic intrusive igneous rock)

Banded Chert (River Stone)

Silicon Dioxide (SiO2)

Basalt (Crushed Stone Aggregate)

Mafic Volcanic Basalt (Major Minerals: Plagioclase Feldspar, Pyroxene, Olivine)

Limestone (specifically a Crushed Aggregate fragment)

Calcium Carbonate (CaCO3)

Quartz

Silicon Dioxide (SiO2)

Yellow Quartz (Citrine or Quartzite Pebble)

Silicon Dioxide (SiO2)

Granite

Granite (High-silica plutonic rock)

Agate

Silicon dioxide (SiO2)