Sedimentary (Fossilized)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Agate-bearing chert (likely petrified wood or silica-rich breccia)

Microcrystalline quartz/chalcedony, SiO₂, with iron-oxide staining and host-rock fragments

Banded Iron Formation (BIF) with potential Stromatolite/Biogenic Trace

Ferruginous Chert / Banded Iron Formation (BIF)

Petrified Wood

Silicified Wood (SiO2 - Quartz/Chalcendony replacing organic matter)

Fossilized shell or small fossil fragment

Indeterminate fossil; possibly a partial gastropod or bivalve, mineralized with calcite

Amber

Succinite (C10H16O)

Amber

Organic gemstone (Succinite is common if from the Baltic)

Amber

Succinite (with formula approximately C10H16O)

Fossilized bivalve shell fragment

Pectinid or related scallop bivalve; shell originally composed mainly of calcite (CaCO₃)

Fossil bone, possibly a large mammal long-bone fragment

Fossilized cortical bone; taxon indeterminate from the photograph

Fossilized shell fragment, likely bivalve

Bivalvia indet.; commonly preserved as calcite (CaCO₃) shell material

Petrified Wood / Fossilized Wood

Silicified Wood (Silicon Dioxide - SiO2)

Polished amber (likely copal or amber)

Amber: fossilized plant resin, chiefly polymerized diterpenes; copal is younger, partially polymerized resin

Chert Pebble (with fossil shell fragment)

Microcrystalline Quartz (SiO2) with Calcified Invertebrate Impression

Petoskey Stone

Hexagonaria percarinata

Fossilized Crab Carapace (Concretion)

Decapoda (fossil), typically preserved in calcite or siderite concretion

Fossilized Shark Tooth in Matrix

Otodus sp. (likely Otodus obliquus)

Possible fossilized shell or coral fragment

Indeterminate biogenic carbonate, likely calcite (CaCO₃)

Amber

Succinite

Fossil bivalve shell

Bivalvia; shell composed mainly of calcium carbonate (typically aragonite and/or calcite)

Fossilized bivalve shell fragment

Calcitic mollusk shell, commonly Bivalvia; exact genus cannot be determined from the image

Fossilized marine shell fragment

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

Fossiliferous limestone

Bioclastic limestone, predominantly calcite (CaCO₃)

Fossilized Sea Urchin (Echinoid)

Echinoidea (Class) - likely replaced by Calcite or Quartz

Fossilized Shark Tooth (Eroded)

Carcharodon sp. or Otodus sp. fragment (likely)

Fossilized wood (petrified wood)

Silicified fossil wood; commonly quartz/chalcedony (SiO₂) replacing wood

Fossilized wood, likely silicified petrified wood

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

Fossilized Echinoid (Sea Urchin) or Brachiopod

Echinoidea / Invertebrate Fossil

Fossil shark tooth in limestone

Selachii indet.; calcitic fossil embedded in carbonate rock

Chert (and Fossilized Brachiopod shell)

Sedimentary Cryptocrystalline Quartz (SiO2)

Fossilized shell or coral fragment

Indeterminate fossil; possibly a gastropod/bivalve fragment or colonial coral

Fossiliferous limestone with a bivalve fossil

Calcareous sedimentary rock; likely molluscan shell fossil, composed chiefly of calcite (CaCO₃)

Fossilized Shark Teeth in Matrix

Cretaceous Chondrichthyes (Shark) remains in Sedimentary Matrix

Fossilized bivalve shell fragment

Bivalvia; commonly aragonite or calcite (CaCO₃), often recrystallized during fossilization

Fossiliferous Sandstone / Quartzite Pebble

Sedimentary rock with skeletal fragments (e.g., Paleozoic crinoid/brachiopod fossils)

Petoskey Stone

Hexagonaria percarinata

Crinoid Stem Columns (Fossil)

Crinoidea (Class); often composed of the mineral Calcite (CaCO3)

Fossilized turtle shell or carapace

Testudines indeterminate; shell mainly fossilized calcium-carbonate bone (apatite)

Fossilized shell-bearing limestone

Fossiliferous limestone, likely containing brachiopod or bivalve remains; exact taxon requires microscopy

Fossilized bivalve shell fragment

Fossil Mollusca, likely a bivalve (class Bivalvia); exact genus cannot be determined from the image

Fossilized bone fragment (tentative)

Petrified bone; mineral replacement commonly by microcrystalline quartz, calcite, or iron oxides

Possible fossilized bone fragment

Fossil bone, composition primarily carbonate-hydroxylapatite [Ca₅(PO₄)₃(OH)]