Man Made Material, Not A Natural Rock Or Mineral Specimen

Unakite

Unakitized granodiorite / Quartz-Epidote-Feldspar rock

Granodiorite / Granite

Granodiorite (containing Quartz SiO2, Plagioclase Feldspar, and Biotite)

Amethyst Quartz

Amethyst (SiO2 with Iron impurities)

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Jasper with Quartz Veining

Silicon Dioxide (SiO2) - Opaque cryptocrystalline variety of Quartz

Granite Cobble

Phaneritic Plutonic Felsic Rock

Blue Chalcedony

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Turquoise

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

Amygdaloidal Basalt

Basalt with secondary mineral infilling (commonly Zeolite, Calcite, or Quartz)

Amethyst Geode

Silicon Dioxide with trace inclusions of Iron (SiO2)

Limestone

Calcite (CaCO3)

Garnet Beads

Garnet Group (complex nesosilicates, e.g., Almandine Fe3Al2(SiO4)3)

Red Sandstone

Arenite (Fe2O3-rich)

Quartz Pebble

Silicon Dioxide (SiO2)

Turquoise (Green variety)

Hydrous phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O

Black Spinel

Magnesium Aluminum Oxide (MgAl2O4)

Quartz Geode

Silicon Dioxide (SiO2)

Quartz

Quartz (SiO2 - Silicon Dioxide)

Dalmatian Stone (commonly Dyed)

Dalmatian Jasper (Peralkaline igneous rock)

Bismuth

Bismuth (Bi)

Obsidian (Black)

Obsidian (High-silica volcanic glass)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Peridotite (Dunite)

Peridotite (mostly Olivine: (Mg,Fe)2SiO4)

Chert (with Limestone matrix)

Silicon dioxide (SiO2)

Red Sandstone

Clastic sedimentary rock (primarily SiO2 with Fe2O3)

Ruby in Zoisite (Anyolite)

Anyolite (Combination of Corundum and Zoisite)

Sandstone (Cross-bedded Drill Core)

Clastic Sedimentary Rock (primarily SiO2)

Pyrite

Iron Sulfide (FeS2)

Milky Quartz with Mineral Inclusions

Silicon Dioxide (SiO2)

Pearl

Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3

Quartz Crystal (specifically a small Clear Quartz point)

Silicon Dioxide (SiO2)

Calcite on Limestone (or Fossil)

Calcium Carbonate (CaCO3)

Ferruginous Sandstone

Ferruginous Clastic Sedimentary Rock

Red Jasper

Jasper (Silicon Dioxide, SiO2 with Iron Oxide impurities)

Sandstone (Quartzose Sandstone Pebble)

Arenite (primarily SiO2)

Sandstone

Sandstone (clastic sedimentary rock, predominantly SiO2)

Yellow Quartz (Citrine/Yellow Chalcedony)

Silicon Dioxide (SiO2)

Granite

Granite (a common rock name, not a single mineral species, composed primarily of quartz, feldspar, and mica/amphibole)

Chatoyant Quartz (Cat's Eye Quartz)

Silicon Dioxide (SiO2) with fibrous inclusions of Amphibole or Rutile

Red Jasper

Jasper (Silicate mineral - SiO2)

Chrysocolla

Hydrated copper silicates (Cu, Al)2H2Si2O5(OH)4·nH2O

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)