Chert (Arrowhead Fragment)
Cryptocrystalline quartz (SiO2)
sedimentary
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Chert / Flint (Arrowhead Artifact)
Microcrystalline quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Sand
Siliciclastic sediment / Quartz sand (SiO2)
sedimentary
Flint
SiO2 (Microcrystalline Quartz / Chert)
sedimentary
Mystic Topaz
Al2SiO4(F,OH)2 (Coated)
gemstone
Agate
Silicon Dioxide (Chalcedony), SiO2
gemstone
Black Tourmaline
Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)4)
mineral
Aquamarine
Beryl (Be3Al2(SiO3)6)
gemstone
Limonite
FeO(OH)·nH2O
mineral
Hematite
Hematite (Fe2O3)
mineral
Pink Quartz
Silicon Dioxide (SiO2)
mineral
Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Limonite Concretion / Ironstone
Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O
mineral
Apache Tear
Obsidian (Natural volcanic glass)
igneous
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified wood (primarily quartz, SiO2)
fossil
Boxwork or Septarian Concretion
Septarian nodule / Boxwork weathering
sedimentary
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Greenstone
Metamorphic mafic rock (greenschist facies)
metamorphic
Quartzite with Mafic Inclusion
Metamorphic Quartzite / Mafic Host Rock
metamorphic
Hematite
Iron(III) oxide (Fe2O3)
mineral
K-Feldspar (Potassium Feldspar)
Potassium Feldspar (Microcline / Orthoclase, KAlSi3O8)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Pegmatite (Quartz and Feldspar)
Igneous Pegmatite containing SiO2 and KAlSi3O8
igneous
Granite
Phaneritic Igneous Rock
igneous
Quartz
Silicon Dioxide (SiO2)
mineral
Jasper
Silicon Dioxide (SiO2) with impurities, Microcrystalline Quartz
sedimentary
Jasper
Silicon Dioxide (Microcrystalline Quartz, SiO2)
sedimentary
Basalt with Jasper Vein
Extrusive Igneous Rock with Quartz/Chalcedony Vein
igneous
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Pegmatite
Pegmatite (felsic intrusive igneous rock)
igneous
Quartz
Silicon Dioxide (SiO2)
mineral
Fossiliferous Chert or Agate
Microcrystalline quartz (SiO2) with fossiliferous inclusions
sedimentary
White Quartz
Silicon Dioxide (SiO2)
mineral
Labradorite (Tumbled)
Plagioclase Feldspar (Na,Ca)(Al,Si)4O8
mineral
Amethyst
Quartz (Silicon Dioxide, SiO2)
gemstone
Flint in Limestone (Chert Nodule)
Sedimentary rock containing microcrystalline quartz (SiO2) within a carbonate matrix
sedimentary
Jasper and Basalt River Pebble
Silica-rich volcanic rock with iron oxide staining
igneous
Agate
Chalcedony (SiO2)
sedimentary
Flint / Chert
Silicon dioxide (Microcrystalline quartz, SiO2)
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary