Igneous And Fossil

Obsidian and Fossilized Shark Tooth

Obsidian (Volcanic Glass) and Otodus sp. (Fossilized shark tooth)

Fossiliferous limestone

Bioclastic limestone, commonly crinoidal or shelly limestone (calcite, CaCO₃)

Fossiliferous limestone (reef or shell-rich limestone)

Bioclastic calcarenite/calcirudite; predominantly calcite (CaCO₃)

Fossilized bivalve shell fragment

Fossil Mollusca, likely a pectinid or related bivalve; exact identification requires the other shell half and locality

Fossiliferous limestone, likely coral or shell-rich fragment

Calcite (CaCO₃), commonly bioclastic limestone containing fossilized marine organisms

Weathered limestone or calcareous sandstone

Calcitic carbonate rock, likely limestone (CaCO₃), possibly slightly dolomitic

Fossil coral limestone

Fossilized colonial coral, commonly tabulate or rugose coral in calcite-rich limestone (CaCO₃)

Fossiliferous limestone fragment

Calcitic limestone; mainly calcium carbonate (CaCO₃), possibly with shell or coral debris

Fossil gastropod in granite-like stone

Gastropoda indet.; enclosing rock likely polished granite or gneiss

Fossilized coral fragment

Fossil scleractinian coral; commonly calcite/aragonite replaced by calcite (CaCO₃)

Probable fossil-bearing rock or mineral concretion

Unidentified carbonate-rich concretion with a possible fossil inclusion

Vesicular basalt (possibly weathered scoria)

Basaltic volcanic rock; chiefly plagioclase, clinopyroxene, and Fe–Mg oxides, with vesicles from trapped gas

Likely fossil oyster shell

Fossilized bivalve shell; exact species cannot be identified from the image

Fossilized marine shell fragment

Likely a bivalve or gastropod shell preserved as calcite (CaCO₃)

Polished granite countertop with fossil shell

Granite; shell likely a fossilized bivalve or gastropod

Conical fossil shell or shell fragment

Likely a gastropod shell fragment; exact taxon indeterminate from the image

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

Tumbled snowflake obsidian

Obsidian (volcanic glass), commonly with cristobalite spherulites

Kambaba Jasper

Rhyolite (Volcanic rock) or Stromatolite (debated)

Petrified wood

Silicified wood; commonly quartz/chalcedony (SiO₂) replacing organic tissue

Polished fossil coral

Fossilized coral, commonly agatized coral (silica replacing CaCO₃)

Likely weathered fossil shell or fossiliferous limestone

Indeterminate molluscan fossil, possibly a bivalve or brachiopod preserved in carbonate rock

Dalmatian jasper (likely orbicular rhyolite)

Silica-rich rhyolite, commonly sold as Dalmatian jasper; typically quartz, feldspar, and dark amphibole/biotite inclusions

Pyrite

Iron Sulfide (FeS2)

Likely weathered vesicular volcanic rock

Probable basaltic scoria or vesicular andesite; exact identification requires testing

Fossiliferous limestone (likely a crinoidal or shell-fragment limestone)

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

Vesicular basalt (likely weathered scoria)

Basaltic volcanic rock; chiefly plagioclase, clinopyroxene, and olivine with vesicles

Orbicular granite (likely rapakivi-type granite)

Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende

Rounded sedimentary pebble

Likely micritic limestone or calcareous sandstone

Pyrite

Iron sulfide (FeS2)

Fossilized bone fragment (probable mammalian tooth or bone)

Mineralized bone, commonly hydroxyapatite [Ca5(PO4)3(OH)] replaced or impregnated by silica/calcite

Pyrite

Iron Disulfide (FeS2)

Vesicular basalt (scoria-like volcanic rock)

Basalt, composed mainly of plagioclase, pyroxene, and olivine; abundant vesicles formed by trapped gas

Vesicular basalt

Basalt, predominantly plagioclase + pyroxene ± olivine; vesicles formed by trapped volcanic gas

Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

Weathered granitic or metamorphic rock fragment

Indeterminate; likely quartz–feldspar–mica-bearing granitoid or gneiss

Fossil-bearing fine-grained sedimentary rock

Likely fossiliferous mudstone or shale; visible feature may be a plant fragment, trace fossil, or mineral vein

Fossiliferous limestone

Bioclastic carbonate rock; predominantly calcite (CaCO₃), with fossil shell fragments

Sedimentary Outcrop (Sandstone/Shale)

Sedimentary bedrock formation (variable composition)

Fossil shark tooth

Likely fossilized shark tooth, possibly Carcharhinus or Otodus species

Fossilized bivalve shell or shell-rich limestone

Likely an indeterminate fossil mollusk; calcite/aragonite (CaCO₃), possibly preserved in limestone

Weathered fossiliferous limestone

Calcitic limestone; predominantly CaCO₃, possibly containing a fossil mold or shell fragment