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Aura Quartz

Titanium-coated Silicon Dioxide (SiO2)

Limonite/Goethite Nodule

Iron Oxyhydroxide (primarily FeO(OH)·nH2O)

Quartzite

Quartzite (composed primarily of Quartz, SiO2)

Chert (Iron-stained)

Chert (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Dyed Agate

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Bauxite

Bauxite (Al2O3·2H2O)

Red Jasper (River Pebble)

Jasper (Silicon Dioxide, SiO2)

Native Copper Nugget

Native Copper (Cu)

Red Quartzite

Quartzite (SiO2 with iron oxide impurities)

Agate (specifically Chalcedony/Banded Agate)

Silicon Dioxide (SiO2)

Marble

Recrystallized Calcite (CaCO3)

Granite (Weathered)

Phaneritic Plutonic Rock (primarily Quartz, Feldspar, and Mica)

Amethyst

Quartz (Silicon Dioxide, SiO2) with iron impurities

Chalcedony (specifically Blue Chalcedony or Common Opal variety)

Silicon Dioxide (SiO₂)

Bauxite

Bauxite (Al(OH)3, γ-AlO(OH), and α-AlO(OH))

Jadeite Jade

NaAlSi2O6 (Sodium Aluminum Silicate)

Gold Ore in Quartz/Matrix

Native Gold (Au) in Quartz (SiO2) matrix

Granite

Granite (Felsic intrusive igneous rock)

Chert (Jasper transition)

Microcrystalline Quartz (SiO2)

Green Fluorite

Fluorite (Calcium Fluoride, CaF2)

Dyed Quartz Geode

Silicon Dioxide (SiO2) with artificial pigment

Ammonite Fossil (Polished Section)

Ammonoidea (typically mineralized with Calcite CaCO3)

Chert (Jasper variety)

Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Limonite and Goethite on Gossan

FeO(OH)·nH2O

Pyrite in Quartz

Iron Sulfide (FeS2) on Silicon Dioxide (SiO2)

Agate with Quartz Druzy

Silicon Dioxide (SiO2) - Microcrystalline and Macrocrystalline varieties

Bauxite

Bauxite (mixture of Hydrous Aluminum Oxides)

Green Aventurine

Silicon Dioxide (Quartz variety) with Fuchsite inclusions (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)

Bivalve Fossil (Internal Mold/Steinkern)

Class Bivalvia (Fossilized Mold)

Chert (often called Jasper or River Rock)

Chert (SiO2)

Sandstone (likely Quartz Sandstone)

Arenite (SiO2 based)

Chert (containing Flint and Chalcedony)

Microcrystalline Quartz (SiO2)

Tiger's Eye

Tiger's Eye (Pseudomorph of Quartz after Crocidolite), SiO2

Pumice

Pumice (Vesicular felsic extrusive igneous rock)

Quartzite River Rock

Quartzite (SiO2)

Basalt

Extrusive Mafic Igneous Rock (composed primarily of Plagioclase, Pyroxene, and Olivine)

Bauxite

Bauxite (mainly Al(OH)3, AlO(OH))

Aquamarine

Beryl (Be3Al2Si6O18 with iron impurities)