Chert (Yellow/Tan variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Category
Anthropogenic (Man Made Material Mimicking Sedimentary Rock)
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Chert Nodule (Flint)
Chert (Silicon Dioxide, SiO2)
sedimentary
Tumbled chalcedony (likely milky quartz)
Microcrystalline quartz, SiO₂; possibly pale agate or quartzite
mineral
Quartz Sandstone Pebble
Sandstone (SiO2 dominated)
sedimentary
Green-and-white terrazzo (likely serpentine/marble aggregate)
Composite decorative stone; probable serpentinite (Mg₃Si₂O₅(OH)₄) with white calcite marble fragments in cementitious matrix
metamorphic
Flint / Chert
Microcrystalline quartz (SiO2)
sedimentary
Rounded quartz pebble
Quartz (silicon dioxide, SiO₂)
mineral
Mother of Pearl (Nacre)
Calcium Carbonate (primarily aragonite, with conchiolin)
Organic Gemstone/Biomineral
Mother of Pearl (Nacre) / Shell Fragment
Biogenic Calcium Carbonate (Aragonite and Conchiolin)
fossil
Chert or silicified sedimentary fragment (tentative)
Microcrystalline quartz (SiO₂), possibly silicified limestone or fossil-bearing chert
sedimentary
Chert (Black Chert or Flint)
Silicon Dioxide (SiO2)
sedimentary
Slate
Metamorphic pelitic rock
metamorphic
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Limestone
Calcareous sedimentary rock (CaCO3)
sedimentary
Chert Pebble/Nodule
Chert (a microcrystalline or cryptocrystalline sedimentary form of quartz, SiO2)
Sedimentary
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Unidentified gray metallic object
Not determinable from the image; likely a metal screw or manufactured fastener rather than geological material
mineral
Sandstone or Limestone
Sedimentary Rock
Sedimentary
Coquina
Biogenic Limestone (CaCO3)
sedimentary
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (and/or Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (variations include Flint/Jasper)
Cryptocrystalline Quartz (SiO2)
sedimentary
Chert / Jasper
Silicon Dioxide (SiO₂)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Fossilized gastropod (likely nerite or related sea snail)
Gastropoda; shell composed originally of aragonite/calcite, commonly replaced or infilled by calcite
fossil
Coquina
Bioclastic Limestone (composed primarily of CaCO3)
sedimentary
Fossilized Shark Tooth (Eroded)
Carcharodon sp. or Otodus sp. fragment (likely)
fossil
Chert Nodule
Microcrystalline Quartz
sedimentary
Chert (often called Flint or Jasper if reddish)
Microcrystalline Quartz (SiO2)
sedimentary
Likely smoky quartz pendant
Smoky quartz, silicon dioxide (SiO₂), quartz variety colored by irradiation-related defects
gemstone
Breccia
Breccia
sedimentary
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
sedimentary
Tumbled chalcedony or quartz pebble
Microcrystalline quartz (SiO₂), likely orange chalcedony/carnelian
mineral
Petoskey Stone
Hexagonaria percarinata (Fossilized Coral)
sedimentary
Fossilized Shell Impression / Siltstone Fossil
Bivalvia / Brachiopoda mold in Siltstone
fossil
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Diamond (as set in a metal alloy ring)
Diamond (Pure Carbon, C)
mineral
Fossilized Shark Tooth
Carcharocles sp. or Striatolamia sp. (Phosphate/Carbonate mineralized Hydroxyapatite)
sedimentary
Chert (Flint)
Chert (SiO2)
sedimentary
Marble
Marble (metamorphosed limestone/dolostone). Predominantly composed of Calcite (CaCO3) for marble derived from limestone, or Dolomite (CaMg(CO3)2) for marble derived from dolostone.
Metamorphic Rock
Chert (Flint/Chalcedony)
Silicon Dioxide (SiO2)
sedimentary
Chalcedony (Agate/Chert variety)
Silicon Dioxide (SiO2)
mineral