Mineralized Fossil

Polished orbicular granite (likely K2 granite or a related mottled granitoid)

Quartz–feldspar–amphibole granitoid; exact identification requires testing

Tumbled dendritic agate (likely)

Chalcedony, microcrystalline SiO₂, with dark manganese/iron-oxide inclusions

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

Siderite Concretion (Nodule)

Iron Carbonate (FeCO3) Concretion

Concretion in Shale

Siltstone/Shale with Siderite or Calcareous concretions

Fossiliferous shale or mudstone with a brachiopod fossil

Likely a spiriferid brachiopod fossil in dark shale/mudstone; exact species and age require locality and examination

Belemnite Fossil (Guardsman Fossil)

Belemnitella spp. (Rostrum)

Fossil oyster shell

Fossilized bivalve, likely Ostrea or a related oyster genus; calcite (CaCO₃) shell

Fossilized Bone Chunk (likely Dinosaur or Large Mammal)

Permineralized Fossil Bone

Fossilized Bivalve Shell

Bivalvia (fossil specimen)

Crinoid Fossil Fragment

Crinoid stem fossil (Echinodermata)

Fossilized Coral (Petoskey-like or Favosites)

Anthozoa (Fossilized Coral)

Fossiliferous Sandstone (with Brachiopod or Bivalve mold)

Clastic Sedimentary Rock with Macrofossil Mold

Epidote–garnet skarn (probable copper-bearing alteration rock)

Calc-silicate skarn; likely epidote, garnet, chlorite, quartz/calcite, and iron oxides/sulfides

Weathered sulfide-bearing metamorphic rock, possibly pyrite-rich schist

Quartz–mica schist with iron sulfides (likely pyrite, FeS₂); exact identification requires testing

Weathered greenish mafic rock fragment

Likely altered basalt or basaltic-andesite; exact identification is uncertain from the photograph

Limonitic ironstone / weathered iron-rich rock

Goethite–limonite aggregate; principally FeO(OH)·nH₂O with possible hematite (Fe₂O₃)

Possible weathered iron-rich rock or breccia

Indeterminate; likely iron-oxide-stained silicate rock, possibly basaltic breccia or limonite-bearing material

Likely iron-rich chert or jasper

Microcrystalline quartz (SiO₂), variably stained by iron oxides/hydroxides

Brachiopod Fossil

Phylum Brachiopoda (order potentially Spiriferida)

Bivalve Fossil (Internal Mold)

Bivalvia (Phalladomya or similar genus)

Sandstone with Fossil Leaf Impression

Sedimentary rock (Sandstone/Siltstone matrix) with Carbonaceous film fossil

Fossilized Bivalve Shell

Bivalvia (Phylum Mollusca)

Fossil Brachiopod or Mollusk Cast

Phylum Brachiopoda / Mollusca internal mold

Tumbled fossiliferous limestone

Bioclastic limestone, primarily calcite (CaCO₃)

Chert or flint with chalcedony/quartz veins

Microcrystalline silica: primarily quartz (SiO₂), including chalcedony; possible fossiliferous limestone or silicified material

Fossiliferous limestone

Bioclastic limestone, primarily calcite (CaCO₃)

Purple druzy quartz (likely dyed or coated)

Quartz, SiO₂ (trigonal crystal system)

Fossiliferous Rock (Invertebrate Fossil in Matrix)

Fossiliferous limestone or shaly matrix containing skeletal fossil remains

Fossilized Shark Tooth

Chondrichthyes (class) fossilized tooth

Petrified Wood

Silicified Wood (SiO2)

Fossilized Gastropod Shell

Class Gastropoda (Fossil)

Fossil Snail

Gastropoda (fossilized)

Weathered copper-bearing porphyritic rock (probable andesite or altered volcanic rock)

Likely propylitically altered andesite/latite; green color may reflect chlorite, epidote, or chrysocolla/malachite staining

Sardonyx Agate Sphere

Cryptocrystalline Quartz (SiO2) with iron oxide inclusions

Fossil Shell (Bivalve)

Class Bivalvia (fossilized)

Fossilized Bone

Permineralized Vertebrate Fossil

Fossiliferous limestone

Calcite-rich limestone (primarily CaCO₃), possibly containing fossil shell or coral fragments

Dendritic Agate

Silicon Dioxide (SiO2) with Manganese/Iron Oxide inclusions

Milky quartz vein rock

Quartz-rich hydrothermal vein; predominantly silicon dioxide (SiO₂), with minor iron-oxide staining and possible feldspar or host-rock fragments

Iron-rich rock or Concretion

Ironstone or Limonite concretion

Orbicular/mafic river pebble with dark dendritic mineral patterns

Likely altered basalt or andesite; dark markings may be manganese-oxide dendrites (MnO₂-rich coatings)