Not A Rock (Synthetic Material)

Amazonite

Amazonite (KAlSi3O8 - Microcline)

Basalt

Aphanitic mafic volcanic rock (primarily plagioclase feldspar and pyroxene)

Chalcedony

Cryptocrystalline Quartz (SiO2)

Limestone (River Pebble)

Sedimentary Calcium Carbonate (CaCO3)

Quartz (specifically Rose or Smoky tinted Quartz)

Silicon Dioxide (SiO2)

Common Opal with Host Rock

Opal (Hydrated silica, SiO2·nH2O)

Bauxite

AlOx(OH)3-2x (mixture of Gibbsite, Boehmite, and Diaspore)

Quartzite

Quartzite (principally SiO2)

Arkosic Sandstone (or Conglomeritic Sandstone fragment)

Arkose (rich in feldspar)

Bumblebee Jasper

Fossiliferous Calcite containing Orpiment and Realgar

Slag

Anthropogenic glassy silicate

River Rock (likely Quartzite or Quartz-rich Siltstone)

Quartzite (SiO2)

Chert (and Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartzite (Iron-stained)

Quartzite (mostly SiO2)

Hematite

Iron(III) oxide (Fe2O3)

Pyrite in Matrix (Commonly called Fool's Gold)

Iron Sulfide (FeS2)

Smoky Quartz Cluster

Smoky Quartz (Silicon Dioxide - SiO2)

Amethyst

SiO2 (Silicon Dioxide) - Purple variety of Quartz

Dalmatian Jasper (or Dalmatian Stone)

Dalmatian Stone (A peralkaline felsite composed of feldspar, quartz, and sodic amphibole)

Granite

Phaneritic Plutonic Igneous Rock (composed of quartz, alkali feldspar, and plagioclase)

Dyed Pumice

Vesicular Rhyolite (Artificial Coloration Addition)

Ferruginous Sandstone

Sandstone (arenite) with Limonite/Goethite cement

Limonite / Ironstone Nodule

Limonite (Hydrated iron(III) oxide-hydroxide), FeO(OH)·nH2O

Tektite (likely Indochinite)

Tektite (high-silica impact glass)

Dalmation Stone

Peralkaline Rock (mixed silicate minerals)

Obsidian

Obsidian (Volcanic Glass) SiO2 (70% or more)

Quartzite Pebble

Quartzite (SiO2)

Carnelian Agate

Carnelian (Silicon Dioxide - SiO2)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Amethyst Quartz

Amethyst (Silicon Dioxide, SiO2)

Moonstone

Feldspar (Orthoclase with Albite), (K,Na)AlSi3O8

Carnelian Agate

Silicon Dioxide (SiO2) with Iron Oxide impurities

Amethyst (Raw Quartz)

Silicon Dioxide (SiO2)

Quartzite (Pink/Red variety)

Quartzite (SiO2 with iron oxide impurities)

Desert Rose (also known as Sand Rose)

Gypsum (CaSO4·2H2O) or Barite (BaSO4) with sand inclusions

Schist

Chlorite/Mica Schist

Amethyst

Amethyst (Silicon Dioxide - SiO2 with ferric impurities)

Sandstone (with Manganese staining)

Arenite (composed primarily of SiO2)

Carnelian

SiO2 (Silicon Dioxide) - Carnelian Agate/Chalcedony

Amethyst Geode (Thunderegg)

Silicon Dioxide (SiO2) - Quartz Variety: Amethyst

Quartz (likely Herkimer Diamond style)

Silicon Dioxide (SiO2)

Jasper pebble

Silicon dioxide (SiO2) with iron oxide inclusions