Organic (Biological Organism)

Amber

Succinite (Formula: C10H16O)

Black Limestone with Calcite Veins

Limestone (Calcium Carbonate, CaCO3)

Coal (likely bituminous coal)

Bituminous coal; predominantly carbon with organic macerals and minor clay/pyrite

Weathered coal-bearing sedimentary rock (likely shale or mudstone with coal fragments)

Carbonaceous shale/mudstone; predominantly clay minerals, quartz, and organic carbon

Petrified Wood

Silicified Wood (primarily quartz/chalcedony replacing organic wood structure)

Amber (Copal)

Organic gemstone, fossilized tree resin (often immature amber or copal)

Fossilized Brachiopod

Brachiopoda (likely Order Spiriferida or Productida)

Likely coal (possibly anthracite)

Coal, composed chiefly of carbon-rich organic matter; rank cannot be confirmed from the photograph

Tumbled brown chert (likely flint)

Microcrystalline quartz/chalcedony, SiO₂

Fossiliferous limestone

Bioclastic carbonate rock; predominantly calcite (CaCO₃)

Fossilized bone fragment

Petrified vertebrate bone; mineralized hydroxyapatite replaced or infilled by silica/carbonates

Polished amber (likely copal or amber)

Fossilized tree resin; amber is predominantly polymerized diterpenoid resin, while copal is younger, incompletely polymerized resin

Fossiliferous limestone

Bioclastic limestone, primarily calcite (CaCO₃), containing marine shell or coral fossils

Septarian nodule (likely polished)

Calcite- and/or aragonite-filled mudstone concretion; commonly Fe-bearing claystone/mudstone matrix

Gastropod Fossil

Phylum Mollusca, Class Gastropoda

Ironstone Concretion (Boxwork)

Siderite-Limonite Concretion (FeO(OH)·nH2O)

Chert Nodule

Microcrystalline Quartz (SiO2)

Unidentified Dark Mineral or Rock

Indeterminate (Likely Silicon Dioxide or Carbon-based)

Polished green moss agate cabochon

Moss agate: microcrystalline quartz (SiO₂) with included chlorite/actinolite or iron-manganese minerals

Amber

Fossilized Tree Resin

Fluorite

Fluorite (CaF2)

Amber

Fossilized tree resin

Fossilized Coral

Cnidaria fossil / Calcite-replaced coral

Limestone

Calcareous sedimentary rock (primarily CaCO3)

Amber

Succinite (fossilized tree resin)

Amber

Succinate (Succinite for Baltic varieties)

Amber

Succinite (fossilized resin)

Chert (Flint)

Silicon dioxide (SiO2)

Limestone (River Stone)

Calcite-rich Sedimentary Rock (CaCO3)

Moss Agate

Silicon Dioxide with inclusions (SiO2 + Mn/Fe/Chlorite)

Amber

Succinite (Resin)

Fossilized Solitary Rugose Coral

Order Rugosa (commonly Horn Coral)

Amber

Succinates (Fossilized Resin)

Amber

Succinite (approximate formula C10H16O)

Chert (containing a small fossil)

Microcrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Fossiliferous Limestone

Calcium carbonate (CaCO3) with marine fossils

Amber

Succinite (C10H16O)

Amber

Succinite (approximate formula C10H16O)

Amber

Succiniferous fossil resin (C10H16O)

Petrified Wood

Silicified Wood (primarily SiO2)

Pearl

Nacre (Aragonite and Conchiolin), CaCO3