Anthropogenic Specimen (Man Made)

Quartzite Pebble (River Rock)

Quartzite (primarily SiO2)

Granitoid (Granite/Gneiss)

Granitoid silicate rock, primarily quartz and feldspar

Pink Granite (Gneissic transition)

Pink Biotite Granite

Citrine Quartz

Silicon Dioxide (SiO2)

Diabase (Greenstone)

Diabase or Dolerite

Limestone (specifically Crushed Limestone/Calcictic)

Calcium Carbonate (CaCO3)

River Cobble (Phyllite or Quartzite)

Metasedimentary Rock (often containing SiO2 or KAl2(AlSi3O10)(OH)2)

Celestite (Celestine)

Strontium sulfate (SrSO4)

Basalt with Quartz Veining

Basalt (Mafic Extrusive Igneous Rock) with SiO2 (Silicon Dioxide) veins

Quartzite Cobble

Quartzite (SiO2)

Petrified Dinosaur Bone (Gembone)

Agatized Dinosaur Bone

Aragonite (Botryoidal/Coralloidal variety)

Aragonite (CaCO3)

Malachite and Azurite on Gossan (Ironstone Matrix)

Cu2CO3(OH)2 (Malachite) on FeO(OH)·nH2O (Limonite/Gossan)

Chert (Arrowhead Preform or Flake)

Microcrystalline Quartz (SiO2)

Milky Quartz Geode Fragment

Silicon Dioxide (SiO2)

Dyed Pumice

Vesicular Rhyolite (Artificial Coloration Addition)

Vesicular Basalt or Scoria

Basalt (extrusive volcanic rock)

Vesicular Basalt with Oxidation

Scoriaceous Olivine Basalt (Mafic volcanic rock)

Granite

Phaneritic plutonic rock (approx. 20-60% quartz, 35-90% feldspar)

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Cobaltian Calcite (Cobaltoan Calcite)

Cobalt-bearing Calcite (Ca,Co)CO3

Quartz Geode

Silicon Dioxide (SiO2) within a geode

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily Quartz with Limonite/Goethite staining)

Basalt Beach Pebble

Basalt (Aphanitic Mafic Volcanic Rock)

Basalt

Basalt (dominated by plagioclase feldspar and pyroxene)

Basalt (River Stone)

Basalt

Basalt River Stone

Basalt (Aphanitic Mafic Igneous Rock)

Ferruginous Sandstone (with possible trace fossils)

Arenite with Iron-Oxide Cement (SiO2 with Fe2O3)

Quartzite Pebble

Quartzite (mostly SiO2)

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Jasper

Silicon dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Chert Pebble

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz (Flesh-colored or Rose Quartz variety)

Silicon Dioxide (SiO2)

Dyed Pink Agate Slice

Cryptocrystalline variety of Quartz (SiO2)

Quartz (Milk Quartz Cobble)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Gneiss (with Quartzite and Biotite)

Gneiss containing SiO2 (Quartz), K(Mg,Fe)3AlSi3O10(OH)2 (Biotite), and (K,Na,Ca)AlSi3O8 (Feldspar)

Quartzite Pebble

Quartzite (SiO2)

Selenite (Satin Spar)

Gypsum (CaSO4·2H2O)

Quartz (River Pebble)

Silicon Dioxide (SiO2)