Mineral Like Biological Tissue

Fossiliferous limestone pebble

Calcite-rich limestone (CaCO₃), containing weathered shell or crinoid fragments

Amber

Fossilized tree resin (not a true mineral as it is organic and amorphous); Chemical formula is highly variable, but often approximated as C10H16O.

Weathered limestone pebble

Calcite-rich limestone (predominantly CaCO₃); exact identification is uncertain from the image alone.

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with organic fossil inclusions

Limestone with Lichen

Sedimentary Calcium Carbonate (CaCO3)

Desert Varnish (on Sandstone)

Rock Varnish (composed of Manganese oxides, Iron oxides, and Clay minerals)

Pearl

Calcium Carbonate (Aragonite or Calcite) and Conchiolin

Amber

Succinite (C10H16O)

Fossil coral limestone

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

Fossiliferous Limestone (Crinoidal)

Crinoid Limestone (CaCO3 with fossil biological remains)

Amber

Succinite (specifically for Baltic amber); Complex mixture of organic compounds (C10H16O)

Porous limestone fragment

Calcite-rich limestone (CaCO₃), possibly bioclastic limestone

Sulfur on Aragonite

Sulfur (S) and Aragonite (CaCO3)

Pearl oyster shell with cultured pearls

Mollusk shell (likely Pinctada spp.) containing aragonite pearls, CaCO₃

Granite with a polished dark-red granite cobble

Granite; predominantly quartz, feldspar, and mica

Crushed Limestone

Calcium Carbonate (CaCO3)

Amber

Succinite (a variety of fossilized tree resin); chemical formula appx. C10H16O

Amber

Succinite

Fossiliferous limestone, possibly a shell or bone fragment

Calcitic limestone; predominantly calcium carbonate (CaCO₃), likely calcite

Fossiliferous Limestone

Fossiliferous Calcilutite / Biomicrite

Weathered limestone fragment

Limestone, primarily calcite (CaCO₃)

Fossil shell fragment

Indeterminate molluscan bioclast, likely aragonite or calcite

Porous limestone (likely fossiliferous or reef limestone)

Calcite-rich carbonate rock; predominantly CaCO₃

Note: Image shows a biological specimen (Rat), not a rock. Representative geological equivalent: Galena (due to lead-grey colors in fur).

Galena (PbS)

Likely vertebra fossil or bone fragment

Indeterminate fossilized vertebra; mineralized hydroxyapatite, commonly Ca₅(PO₄)₃(OH)

Banded chert or siliceous shale

Microcrystalline quartz (SiO₂), possibly interbedded with carbonaceous or clay-rich shale

Fossilized shell or coral fragment

Indeterminate calcareous fossil; likely aragonite/calcite (CaCO₃)

Pyritic Shale

Carbonaceous Shale with Iron Pyrite (FeS2)

Shell Cameo

Cypraecassis rufa (Bullmouth Queen Helmet Shell)

Hag Stone (Banded Chert or Limestone with Borehole)

Microcrystalline Quartz (Chert) or Calciferous Siltstone (CaCO3/SiO2)

Limestone with Chert

Sedimentary Rock (CaCO3 with SiO2 inclusions)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Sea Shell (Mollusk Shell)

Calcium Carbonate (Aragonite/Calcite)

Amber

Succinite (specific to Baltic amber), fossilized tree resin

Honeycomb Coral Fossil

Favosites (extinct genus of tabulate coral)

Porous limestone (likely coral limestone)

Calcite-rich carbonate rock; primarily calcium carbonate, CaCO₃

Rounded brown pebble, likely chert or iron-stained quartzite

Chert (microcrystalline quartz, SiO₂) or quartzite (recrystallized quartz, SiO₂)

Fossiliferous Limestone

Sedimentary Calcium Carbonate (CaCO3)

Coquina / Fossiliferous Limestone

Coquina (composed primarily of Calcium Carbonate / CaCO3)

Limestone (Decorative Gravel)

Calcium Carbonate (CaCO3)

Polished fossiliferous limestone (likely crinoidal or shell-rich limestone)

Bioclastic limestone, primarily calcite (CaCO₃), containing fossil fragments

Rounded pale pebble, likely limestone

Micritic limestone, primarily calcite (CaCO₃)