Chert (specifically Flint or Common Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Category
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Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, SiO2)
fossil
Stromatolite (Fossiliferous Limestone)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Chert (Yellow Jasper variant)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Yellow Jasper/Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Yellow Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Oak Wood (Wood Grain Pattern)
Quercus (genus)
Organic (Non-rock)
Sandstone with Quartz Crystal Infill
Quartz-cemented quartz arenite
sedimentary
Chert (varieties include Flint and Jasper)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Shale
Fissile mudrock (composed primarily of clay minerals and quartz)
sedimentary
Pearls (likely freshwater cultured pearls)
Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin
gemstone
Anthracite Coal
Anthracite (Carbon-based metamorphic rock, 86-97% C)
metamorphic
Zebra Stone (Banded Chert or Limestone)
Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3) inclusions
sedimentary
Sandstone Concretion with Fossil Wood
Ferruginous Sandstone Concretion (SiO2 with Fe2O3 cement)
sedimentary
Zebra Marble
Metamorphosed Limestone (Recrystallized Calcite)
metamorphic
Amber
Succinite
Organic mineraloid
Pearl
Organic Mineraloid (CaCO3 + Conchiolin)
mineral
Moss Agate
Chalcedony (SiO2) with inclusions of hornblende or chlorite
mineral
Fossiliferous Shale
Laminated Mudrock with plant fossils
sedimentary
Stromatolite
Biogenic Sedimentary Rock (composed predominantly of CaCO3)
sedimentary
Bituminous Coal
Organic sedimentary rock (humic coal)
sedimentary
Dendritic Agate
Silicon Dioxide with inclusions (SiO2 + Mn/Fe)
mineral
Shale
Mudrock / Fissile Shale
sedimentary
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with Bioclasts
sedimentary
Dendritic Agate
Chalcedony (SiO2) with manganese/iron oxide inclusions
mineral
Ferruginous Sandstone (Ironstone)
Sedimentary rock with Limonite/Goethite cement
sedimentary
Pink Opal (Common Opal)
Amorphous Hydrated Silica (SiO2·nH2O)
mineral
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Amber
Succinite (approximate formula C10H16O)
mineral
Chert Nodule
Microcrystalline Quartz (SiO2)
sedimentary
Amber
Succinate (Fossilized Tree Resin)
mineraloid
Amber
Succinate (Fossilized Tree Resin)
mineraloid
Amber (Rough)
Amber (Fossilized Tree Resin, succinite)
mineral
Amber
Succinicum (Organic Gemstone - Resinite)
mineraloid
Amber
Fossilized Tree Resin (Succinate)
mineral
Moss Agate and Hematite
Silica (SiO2) with fibrous inclusions of Manganese or Iron; Hematite (Fe2O3)
mineral
Tahitian Pearl
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
mineral
Fossiliferous Limestone Pebble
Calcite-rich Fossiliferous Marine Limestone
fossil
Amber
Fossilized Tree Resin (Organic Polymer)
gemstone