Not A Rock Or Mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz Geode

Silicon Dioxide (SiO2) in a Secondary Sedimentary/Volcanic cavity

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Goldstone

Avventurina (Cu + SiO2 glass)

Turquoise

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

Basalt

Mafic volcanic rock (formula varies by mineral content: Ca-plagioclase, Pyroxene, Olivine)

Granite

Granite (a common rock type, not a single mineral species)

Sandstone

Arenite (primarily SiO2)

Sandstone

Sandstone (principally SiO2)

Chert (with Quartz Veining)

Microcrystalline Quartz (SiO2)

Chert (Nodule)

Chert (composition: SiO2)

Porphyritic Basalt (River Rock)

Porphyritic Basalt

Gneiss

Gneiss (pronounced 'nice')

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Basalt

Basalt (Mafic Extrusive)

Ferruginous Sandstone

Clastic sedimentary rock (primarily Quartz with Iron Oxide cement)

Bituminous Coal (with Anthracite or Vitrinite inclusion)

Organic-rich Sedimentary Rock (Carboniferous classification)

Red Jasper

Red Jasper (SiO2 with Fe2O3 impurities)

Sandstone Pebble with Iron Staining

Clastic Sedimentary Rock (primarily Quartz with Fe2O3 oxides)

Septarian Nodule Segment (Turtle Stone)

Septarian Concretion (CaCO3 with Siderite or Calcite infill)

Amethyst

Amethyst (Silicon Dioxide, SiO2)

Grey Granite

Phaneritic Felsic Intrusive Igneous Rock

Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Gold Nugget

Native Gold (Au)

Mica Schist

Crystalline Schist (often primarily Muscovite or Biotite sheet silicates)

Amethyst

SiO2 (Silicon Dioxide with Iron impurities)

Citrine

Citrine (Silicon Dioxide - SiO2)

Graphite-veined Quartzite

Meta-sedimentary Quartzite with Carbonaceous/Graphitic Inclusions (SiO2 + C)

Mahogany Obsidian

Volcanic Glass (with inclusions of Magnetite or Hematite)

Epidosite (Epidote-rich rock)

Epidosite (consisting primarily of Epidote: {Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH))

Obsidian

Obsidian (principally SiO2)

Granite

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

Carnelian

Carnelian (a variety of Chalcedony, SiO2)

Green Aventurine

Silicon Dioxide (SiO2) with Fuchsite inclusions

Chalcedony (variations like Agate or Jasper)

Chalcedony (SiO₂ - microcrystalline quartz)

Tiger's Eye

Pseudomorph of quartz after crocidolite (SiO2 with iron oxide inclusions)

Pink Granite

Phaneritic Felsic Intrusive Igneous Rock

Red Sandstone

Arenite (with Iron Oxide / Hematite), Formula: SiO2 (Quartz) + Fe2O3 (Hematite coating)

Sandstone (Ferruginous)

Arenite with Iron Oxide (Fe2O3) cement

Chert (Agatized/Chalcedony variety)

Microcrystalline Quartz (SiO2)

Quartz (vein quartz)

SiO2 (Silicon Dioxide)

Gneiss

Gneiss (High-grade Regional Metamorphic Rock)