Dark flint or chert fragment
Microcrystalline quartz (SiO₂), likely chert/flint
sedimentary
Category
Sedimentary (Fossilized Organic Matter)
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Chert (likely flint)
Microcrystalline quartz, SiO₂ (chalcedony-rich chert)
sedimentary
Weathered dark flint (chert) pebble
Microcrystalline quartz (SiO₂), commonly called flint or chert
sedimentary
Chert (specifically Gray Chert)
Silicon Dioxide (SiO2)
sedimentary
Pyrite
Iron Disulfide (FeS2)
mineral
Pyrite
Iron Disulfide (FeS2)
mineral
Sandstone Pebble
Arenite (primarily SiO2)
sedimentary
Flint (chert), likely a worked or fractured nodule
Microcrystalline quartz/chalcedony (SiO₂)
sedimentary
Chert (likely flint)
Microcrystalline quartz, SiO₂ (chalcedony/quartz aggregate)
sedimentary
Green Moss Agate
Silicon Dioxide with inclusions (SiO2 + Mn/Fe)
sedimentary
Fossilized Shark Tooth
Carcharocles or Otodus sp. (Micro-fossilized)
sedimentary
Fossiliferous Limestone
Limestone (CaCO3 - Calcium Carbonate)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Fossiliferous Limestone
Calcium carbonate matrix with macrofossils (CaCO3)
sedimentary
Chalcedony in Matrix (likely Agatized Coral or Chert)
Silicon Dioxide (SiO2)
sedimentary
Amber (Copal)
Fossilized Tree Resin (C10H16O)
mineral
Chert (often called Flint)
Chert (Microcrystalline Silicon Dioxide, SiO2)
sedimentary
River Pebble (Siltstone/Mudstone)
Clastic sedimentary rock
sedimentary
Tumbled yellow calcite (probable)
Calcite — calcium carbonate, CaCO₃
mineral
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Chert (Jasper/Flint Pebble)
Microcrystalline quartz (SiO2)
sedimentary
Black Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Anthracite Coal
Anthracite
sedimentary
Chert Concretion (Flint)
Silicon Dioxide (SiO2)
sedimentary
Chert Fossil (Pebble)
Microcrystalline Quartz (SiO2) with biogenic inclusions
sedimentary
Jasper
Cryptocrystalline Quartz (SiO2)
sedimentary
Chert / Jasper / Agate (Chalcedony Group)
Microcrystalline Quartz (SiO2)
sedimentary
Glauconitic Sandstone (Greensand)
Glauconitic Quartz Arenite (containing Glauconite, (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)
sedimentary
Mosasaur Tooth Fossil
Mosasaurus sp.
fossil
Fossiliferous Limestone
Limestone with embedded fossil cross-section
sedimentary
Fossil gastropod shell
Fossilized or mineral-replaced gastropod (class Gastropoda), exact genus indeterminate
fossil
Dendritic Limestone
Calcite with Manganese Oxide (Manganese Dendrites)
sedimentary
Petrified Wood
Silicified wood (primarily Quartz, SiO2)
fossil
Fossilized Tiger Shark Tooth
Galeocerdo cuvier (fossilized hydroxylapatite)
sedimentary
Bivalve Fossil (Internal Mold/Steinkern)
Class Bivalvia (Fossilized Mold)
sedimentary
Calcite
Calcite (calcium carbonate, CaCO₃), likely massive or crystalline limestone-derived material
mineral
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily Chalcedony or Quartz, SiO2)
sedimentary
Ironstone Concretion
Goethite-rich Siltstone / Siderite (FeCO3)
sedimentary
Petrified Wood (Calamites Fossil)
Calamites sp. (Silicified/Permineralized Plant Fossil)
sedimentary