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Banded Chert / Flint

Silicon dioxide (SiO2)

Beach Quartz Pebble

Quartz (Silica - SiO2)

Chert (Nodule)

Cryptocrystalline Silica (SiO2)

Basalt (Water-worn pebble)

Mafic Igneous Rock (primarily Plagioclase feldspar and Pyroxene)

Moss Agate

Silicon Dioxide (SiO2) with mineral inclusions of hornblende or chlorite

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Moonstone

Orthoclase (Potassium Aluminum Silicate), Formula: (K,Na)AlSi3O8

Bumblebee Jasper

Hydrothermal Volcanic Rock (Primarily Calcite with Orpiment - As2S3, Realgar, and Pyrite)

Anthracite Coal

Anthracite

Gold Nugget

Native Gold (Au)

Chert / Flint

Microcrystalline Quartz (SiO2)

Ferruginous Quartz (Iron-Stained Quartz)

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

Titanium Aura Quartz (Aura Quartz)

Titanium-coated Silicon Dioxide (SiO2)

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Chert (Iron-stained)

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Concrete / Anthropogenic Conglomerate

Man-made composite material (Portland cement, aggregate, and water)

Chalcedony (Carnelian variety)

Silicon Dioxide (SiO2)

Apatite

Fluorapatite, Chlorapatite, and Hydroxylapatite (Ca5(PO4)3(F,Cl,OH))

Iron Meteorite (likely Chondrite or Iron-Nickel fragment)

Siderite (Iron Meteorite), primarily Fe-Ni (Iron-Nickel) alloy

Anthracite Coal

Anthracite (Carbon-rich Sedimentary-to-Metamorphic Rock)

Chert (Nodular)

Microcrystalline Silica (SiO2)

Pink Granite

Granite (Phaneritic intrusive igneous rock dominated by Quartz and K-Feldspar)

Yellow Jasper

Silicon Dioxide (SiO2) with goethite or iron oxide inclusions

Green Fluorite

Calcium Fluoride (CaF2)

Jadeite

Jadeite (NaAlSi2O6)

Howlite (Dyed Turquoise)

Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Picture Jasper (specifically Biggs or Deschutes variety)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Rough Green Adventurine

Aventurine (Variety of Quartz, SiO2)

Amazonite

Amazonite (KAlSi3O8)

Amethyst Geode

Amethyst (Silicon Dioxide), Formula: SiO2

Banded Chert (River Cobble)

Microcrystalline Quartz (SiO2)

Quartz nodule (River pebble)

Silicon Dioxide (SiO2)

Greenschist

Chlorite-actinolite schist

Chert / Flint (River Pebble)

Cryptocrystalline Quartz (SiO2)

Quartzite Pebble

Quartzite (SiO2)

Quartzite with Hematite

Metamorphosed Quartz Sandstone (SiO2 with Fe2O3 inclusions)

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Anthracite Coal

Anthracite (Carbon-rich metamorphic rock)

Obsidian

Obsidian (Volcanic Glass), primarily SiO2