Hag Stone
Natural Perforated Flint or Chert (SiO2)
sedimentary
Category
Organic (Biological Organism)
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Fossil crocodilian skull and jaws
Crocodyliform fossil; exact genus and species cannot be determined from the image
fossil
Opalite
Synthetic Opalised Glass
Mineral (Synthetic / Man-made)
Sand Tiger Shark Tooth
Carcharias taurus
fossil
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Vesicular basalt (scoria-like basalt fragment)
Basalt; primarily plagioclase, pyroxene, and commonly olivine, with small vesicles
igneous
Tumbled fossiliferous limestone
Calcite-rich limestone (CaCO₃), possibly containing fossil fragments
sedimentary
Likely bituminous coal
Coal, predominantly carbon-rich organic matter with variable maceral and mineral content
sedimentary
Freshwater Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite organic composite
gemstone
Amber
Fossilized Tree Resin
gemstone
Petrified Wood
Silicified Wood (SiO2 permineralization)
fossil
Honey calcite (likely)
Calcite, calcium carbonate (CaCO₃)
mineral
Fossilized Coral (Petoskey Stone type)
Hexagonaria percarinata (Fossilized Rugose Coral)
fossil
Anthracite Coal
Anthracite (Carbon-based metamorphic rock, 86-97% C)
metamorphic
Sandstone with Quartz Crystal Infill
Quartz-cemented quartz arenite
sedimentary
Coal (Bituminous Coal)
Caustobiolith / Sedimentary Rock
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
sedimentary
Stromatolite (Fossiliferous Limestone)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Marine invertebrate fossils (Brachiopods and Gastropods)
Phylum Brachiopoda and Class Gastropoda
fossil
Amber
Succinates
mineraloid
Siderite Concretion in Shale
Iron carbonate (FeCO3) in Mudstone/Shale matrix
sedimentary
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with Bioclasts
sedimentary
Amber (possibly a small polished amber cabochon)
Fossilized tree resin; amber is an organic gemstone, not a mineral
gemstone
Ambergris (Marine Coprolite/Subfossil)
Marine organic coprolite / Ambergris (Physeter macrocephalus metabolite)
fossil
Anthracite Coal
Anthracite (Carbon-based organic sedimentary/metamorphic rock)
metamorphic
Petrified Wood
Silicified wood (primarily quartz replacing organic cellulose)
fossil
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
Bivalve seashell
Calcareous shell, primarily aragonite (CaCO₃); likely a modern cockle or related bivalve
fossil
Agatized Fossil Coral
Agatized Anthozoa
fossil
Petrified Wood
Silicon Dioxide (SiO2)
fossil
Fossilized Shark Tooth (Megalodon or Carcharocles species fragment)
Otodus megalodon / Carcharocles spp. (Apatite / Calcium Phosphate)
fossil
Fossiliferous Limestone
Calcium Carbonate (CaCO3) matrix with biogenic fragments
fossil
Fossilized Shark Tooth
Chondrichthyes (class)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Chert (varieties include Flint and Jasper)
Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO₂)
sedimentary
Chert (often called Flint)
Chert (Microcrystalline Silicon Dioxide, SiO2)
sedimentary
Chert (specifically Gray/Black Chert)
Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
metamorphic