Synthetic (Not A Rock Or Mineral)

Limonitic Sandstone (Stained Sandstone)

Clastic Sedimentary Rock with Iron Oxide (Limonite/Goethite) staining

Red Sandstone

Arenite (Fe2O3 rich)

Sandstone (with Limonite staining)

Arenite (primarily SiO2 with FeO(OH)·nH2O)

Sedimentary rock with quartz veining

Laminated siltstone or mudstone with hydrothermal quartz veins

Sandstone (likely Arkose)

Arenite (composed mainly of SiO2 with Feldspar)

Geode (Chert or Quartz Nodule)

Silicon Dioxide (SiO2)

Quartz (Variety of Rough Mineral Specimens)

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Grey Agate (Tumbled)

Silicon Dioxide (SiO2)

Quartz with Iron Staining

Silicon Dioxide (SiO2) with Limonite/Hematite inclusions

Sandstone (Red Sandstone)

Arenite (SiO2 based with Fe2O3 staining)

Tree Agate

Dendritic Chalcedony (SiO2)

Sandstone (Stream-rounded)

Arenite (SiO2 based)

Sandstone (Quartzose Sandstone)

Arenite (primarily SiO2)

Conglomerate

Clastic sedimentary rock (Puddingstone)

Carnelian (Chalcedony)

Silicon Dioxide (SiO2)

Quartz with Hematite Staining

Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3) inclusions

Granite

Granite (Felsic Plutonic Rock)

Granite

Granite (composed primarily of Quartz SiO2, Alkali Feldspar KAlSi3O8, and Plagioclase)

Sandstone

Arenite (SiO2 + various cementing minerals)

Black Sand (Magnetite Sand)

Magnetite-rich Placers (Fe3O4)

Dalmatian Stone

Dalmatian Jasper (Aphanitic Igneous Rock with Arfvedsonite inclusions)

Gneiss

High-grade metamorphic rock (Gneiss)

Granite

Granite (a common rock type, not a single mineral with a formula. Composed primarily of quartz, feldspar, and mica/amphibole).

Geode with Iron-Stained Quartz/Calcite

Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3) in Sedimentary Matrix

Quartz Vein on Matrix

Silicon Dioxide (SiO2)

Vesicular Basalt (Iron-Stained)

Mafic Volcanic Rock (Basalt)

Turquoise

Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)

Gneiss

Foliated Metamorphic Rock (Gneiss)

Geode (Unopened)

Silica-rich Concretion (primarily SiO2)

Quartzite / Sandstone / Chert Mix

Silicon Dioxide (SiO2)

Porphyry (likely Porphyritic Andesite or Basalt)

Porphyritic Igneous Rock

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Milky Quartz (with Iron Oxide staining)

Silicon Dioxide (SiO2)

Sandstone

Arenite (primarily composed of SiO2 - Silicon Dioxide)

Mica Schist

Mica Schist (predominantly Muscovite or Biotite sheet silicates)

Sandstone (Stream Pebble)

Arenite (primarily SiO2)

Milky Quartz (Vein Quartz)

Silicon Dioxide (SiO2)

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Banded River Rock / Gneiss (highly weathered)

Gneiss