Man Made Byproduct (Often Mistaken For Obsidian Or Emerald)

Quartz Veined Rock (Likely Graywacke or Quartzite)

Silicon Dioxide (SiO2) veins in Metasedimentary matrix

Diamond

Diamond (pure Carbon, C)

Porphyritic Basalt (with Lath-like Phenocrysts)

Porphyritic Basalt

Milky Quartz

Silicon Dioxide (SiO2)

Conglomerate

Conglomerate (Sedimentary Clastic Rock)

Quartzite

Quartzite (SiO2)

Desert Varnish (on Sandstone)

Rock Varnish (composed of Manganese oxides, Iron oxides, and Clay minerals)

Quartzite Pebble (with Quartz veins)

Quartzite (SiO2)

Cloudy Quartz

Quartz (Silicon Dioxide, SiO2)

Garnet-bearing Schist

Almandine Garnet (Fe3Al2(SiO4)3) in Mica Schist

Milk Quartz (Tumbled)

Silicon Dioxide (SiO2)

Turquoise

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

Sodalite

Sodalite (Na8Al6Si6O24Cl2)

Gold and Diamond

Native Gold (Au) and Diamond (C)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Moss Agate

Silicon Dioxide (SiO2) with inclusions

Amygdaloidal Rhyolite (often called Lake Superior Agate relative)

Rhyolite with Calcite/Quartz amygdules (SiO2 and secondary minerals)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Fossiliferous Limestone (Chertified Limestone)

Calcium Carbonate (CaCO3) often replaced by Microcrystalline Silica (SiO2)

Quartz Pebble

Silicon dioxide (SiO2)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Porphyritic Basalt (Chinese Flower Stone / Chrysanthemum Stone basalt variety)

Porphyritic Basalt containing Plagioclase Feldspar phenocrysts

Quartzite

Quartzite (primarily SiO2)

Quartzite

Metamorphosed Quartz Sandstone (primarily SiO2)

Citrine Quartz

Silicon Dioxide (SiO2)

Agate (specifically, multi-colored or pastel-dyed agate)

Silicon dioxide (SiO2) - specifically, a cryptocrystalline variety of quartz known as Chalcedony, with banding classified as Agate. (If it were Fluorite, the chemical formula would be Calcium Fluoride - CaF2).

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Quartzite with Sandstone/Iron staining

Metamorphic Quartzite (SiO2)

Scoria (Lava Rock)

Vesicular Basalt / Scoria

Quartz Pebble (Sea Glass-like texture)

Silicon Dioxide (SiO2)

Quartzite River Cobble

Quartzite (SiO2)

Black Jasper (Black Stone / River Pebble)

Silicon Dioxide (SiO₂), Opaque variety of Chalcedony

Quartzite

Quartzite (SiO2)

Quartzite

Quartzite (primarily Silicon Dioxide, SiO2)

Rhodonite

Rhodonite (MnSiO3)

Shale creek bed

Shale (fine-grained clastic sedimentary rock)

Biotite Mica

Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)

Lepidolite

K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2 (Lithium-bearing Phyllosilicate)

Pyrite

Iron Sulfide (FeS2)

Chert / Flint Nodule

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz (Iron-stained)

Silicon Dioxide (SiO2)