Chert (specifically Flint or Jasper variant)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Category
Organic Mineraloid
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Petrified Wood
Silicified Wood (SiO2)
sedimentary
Fossilized Shark Tooth
Carcharocles sp. or Striatolamia sp. (Phosphate/Carbonate mineralized Hydroxyapatite)
sedimentary
Pyrite-bearing Schist
Pyritic Quartz-Mica Schist with FeS2 inclusion
metamorphic
Picture Jasper
Silicon Dioxide (SiO2) - Opaque Chert/Quartzite variety
sedimentary
Petrified Wood
Silicified Wood (primarily Quartz or Chalcedony, SiO2)
mineral
Chert with Quartz Druzy
Microcrystalline Quartz (SiO2) with Drusy Quartz Coating
sedimentary
Banded Chert
Microcrystalline silicon dioxide (SiO2)
sedimentary
Chert (Flint variety)
Chert (Microcrystalline or Cryptocrystalline Quartz), SiO2
sedimentary
Chert (Jasper/Common Opal transition)
Microcrystalline Quartz (SiO2) with iron oxide inclusions
sedimentary
Chert / River Pebble
Microcrystalline Silica (SiO2)
sedimentary
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement of organic matter)
sedimentary
Shale
Shale (fine-grained clastic sedimentary rock)
Sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Fossiliferous Limestone containing a Brachiopod or Mollusk Impression
Biogenic Sedimentary Rock / Fossiliferous Limestone
sedimentary
Petrified Wood
Silicified wood (primarily quartz replacing organic cellulose)
fossil
Ambergris (Marine Coprolite/Subfossil)
Marine organic coprolite / Ambergris (Physeter macrocephalus metabolite)
fossil
Anthracite Coal
Anthracite (Carbon-based organic sedimentary/metamorphic rock)
metamorphic
Coal (Anthracite)
Anthracite (Carbon-based organic sedimentary/metamorphic rock)
metamorphic
Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite organic gemstone
mineral
Coal (Bituminous)
Organic sedimentary rock primarily consisting of carbon (C)
sedimentary
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide and organic impurities
sedimentary
Arid Sandy Loam
Arenosols / Regosols
sedimentary
Yellow Jasper (Mookaite style)
Silicon Dioxide (SiO2) with Goethite/Hematite inclusions
sedimentary
Fossil Coral
Phylum Cnidaria / Rugosa or Tabulata
fossil
Moss Agate
Silicon Dioxide (SiO2) with inclusions of hornblende, chlorite, or manganese/iron oxides
mineral
Amethyst Sage Agate
Silicon Dioxide (SiO2) with trace minerals (Manganese/Iron oxides)
mineral
Amber (specifically Cherry Amber)
Succinite (with the chemical formula C10H16O)
Organic Gemstone (not a mineral)
Ironstone / limonite-rich concretion
Hydrated iron oxides, chiefly limonite/goethite (FeO(OH)·nH₂O), possibly with hematite
mineral
Likely tumbled jasper or chert specimens
Microcrystalline quartz (SiO₂), commonly jasper/chert; exact identification is uncertain from the photograph
sedimentary
Fossil Shark Tooth
Chondrichthyes (Class)
fossil
Fossilized Shark Tooth (Fragment)
Elasmobranchii gen. et sp. indet. (Calcium Phosphate / Apatite fossil)
fossil
Petrified Wood
Silicon Dioxide Fossilized Wood (SiO2)
fossil
Lepidodendron Fossil (Scale Tree)
Lepidodendron
fossil
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement of cellulose)
fossil
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement)
fossil
Petrified Wood
Silicified wood (principally SiO2)
sedimentary
Banded Chert / Flint
Microcrystalline Quartz (SiO2)
sedimentary
Jasper (Brown Iron-Rich Variety)
Silicon Dioxide (SiO2) with Fe2O3 (Iron Oxide/Crystalline Quartz)
sedimentary
Zebra Marble
Metamorphosed Alabaster/Limestone (CaCO3)
metamorphic
Chert (with Calcite Veining)
Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3) veins
sedimentary