Sedimentary Rock (Possibly Conglomerate Or Breccia With A Quartz Vein)

Gneiss

Gneiss (High-grade metamorphic rock)

Sandstone

Sandstone (composed primarily of sand-sized minerals or rock grains)

Rhodonite

Manganese Silicate (Mn,Fe,Mg,Ca)SiO3

Amethyst Quartz (Amethyst Geode)

Silicon Dioxide (SiO2) with iron impurities

Red Jasper (Skull Carving)

Jasper, a cryptocrystalline variety of Quartz (SiO2)

Ferruginous Sandstone (Gritstone)

Clastic sedimentary rock with iron-rich cement (FeO(OH)·nH2O)

Quartz (Milky/Clear variety)

Silicon Dioxide (SiO2)

Sandstone (Red)

Arenite (primarily Quartz, SiO2, with Iron Oxide cement)

Jasper (Iron-stained)

Silicon Dioxide (SiO2) with iron oxide inclusions

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Gneiss (specifically Granite Gneiss)

Gneiss (High-grade Regional Metamorphic Rock)

Howlite

Howlite (Calcium borosilicate hydroxide, Ca2B5SiO9(OH)5)

Grey River Pebble (Likely Quartz-rich or Limestone)

Clastic Sedimentary Rock (typically SiO2 or CaCO3 based)

Sandstone (likely Graywacke or Lithic Sandstone)

Arenite / Wacke (SiO2 based with lithic fragments)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Jasper (Red/Brown Variety)

Jasper (Microcrystalline Quartz, SiO2)

Turquoise

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

Turquoise

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

Amethyst

SiO2 (Silicon Dioxide)

Schist

N/A (a rock type, not a mineral formula)

Shale

Fissile Mudstone (primarily composed of clay minerals and quartz grains)

Jasper

Jasper (Cryptocrystalline variety of Quartz, SiO2)

Chert (variously known as Flint or Jasper)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Rock Crystal Quartz Pebble

Silicon Dioxide (SiO2)

Tree Agate

Silicon Dioxide (SiO2) with Chlorite/Manganese inclusions

Chert

Chert (microcrystalline quartz, SiO2)

Agate

Agate (Cryptocrystalline Variety of Quartz, SiO2)

Chert (often called Flint or River Rock)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Banded Gneiss

Gneiss (Metamorphic rock of variable mineralogy, often quartz-feldspar base)

Red Jasper (with Quartz veining)

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

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Chrysoprase

Chalcedony (cryptocrystalline SiO2 variety)

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Shale

Shale (clastic sedimentary rock)

Gneiss

Gneiss (high-grade metamorphic rock typically composed of quartz, feldspar, and mica)

Druzy Quartz (on Geode Fragment)

Silicon Dioxide (SiO2)

Carnelian (Banded Agate)

Carnelian Chalcedony (SiO2)

Quartzite

Quartzite (primarily SiO2)

Note: Image shows a biological specimen (Rat), not a rock. Representative geological equivalent: Galena (due to lead-grey colors in fur).

Galena (PbS)

Amethyst

Quartz (SiO2) with trace iron impurities

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)