Sedimentary (Biogenic)

Weathered fossil shell fragment

Likely molluscan shell, composed mainly of calcium carbonate (aragonite or calcite); exact taxon is indeterminate from the image

Pearl

Calcium Carbonate (Aragonite) - CaCO3

Pearl (Imitation or Cultured)

Calcium Carbonate (Aragonite/Calcite) - CaCO3

Pearl oyster shell with natural pearls

Molluscan shell, likely Pinctada spp.; pearls are aragonite (CaCO₃)

Calcite

Calcite (Mineral; CaCO₃)

Pearl

Aragonite (CaCO3) with Conchiolin

Pearl necklace

Pearl (biogenic calcium carbonate, chiefly aragonite; CaCO₃)

Tahitian Black Pearl

Biogenic Calcium Carbonate (Aragonite/Conchiolin Mixture), CaCO3

Fossilized shell or bone fragment

Indeterminate biogenic carbonate/phosphate fossil; likely a fragment of fossil shell or small vertebrate bone

Beach-worn fossil bone or coral fragment

Indeterminate biogenic calcium-carbonate material; likely fossilized bone (hydroxyapatite) or coral (calcite/aragonite)

Fossiliferous limestone (coral or shell-rich limestone)

Biogenic calcite limestone, mainly calcium carbonate (CaCO₃); exact fossil type is unclear from the image

Pearls (likely freshwater cultured pearls)

Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin

Calcite

Calcite (Calcium Carbonate, CaCO3)

Rounded reddish-brown pebble, likely iron-stained quartzite or chert

Quartzite (mostly SiO₂), possibly ferruginous chert

Pebble (likely Quartz or Chert)

SiO₂ (Silicon Dioxide) - referring to the likely main mineral composition, Quartz. If it's chert, the scientific name remains SiO₂ with a microcrystalline structure.

Fossilized Shark Tooth (Cretaceous to Neogene)

Elasmobranchii dental fossil (likely Squalicorax or similar species)

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

Ferruginous Chert / Banded Iron Formation (BIF)

Pearl-embellished decorative cross

Pearl (biogenic calcium carbonate, predominantly aragonite) with rhinestone-mounted glass or synthetic gemstones

Calcite (likely a tumbled specimen)

Calcite (CaCO 3 )

Calcite

Calcite (CaCO₃)

Queen Conch Shell (Biogenic Calcium Carbonate)

Aliger gigas (synonym Strombus gigas); Composition: Aragonite (CaCO3)

Pearl oyster shell with cultured pearls

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

Weathered quartz-rich rock, likely chert or quartzite

Quartzite/chert; predominantly microcrystalline quartz (SiO₂), with iron-oxide staining and possible minor feldspar or clay minerals

Chert (Jasper or Flint variant)

Chert (composed of microcrystalline quartz, SiO2)

Amber Inlay Jewelry

Fossilized Resin (C10H16O)

Flint

Chert (a form of cryptocrystalline quartz, chemical formula SiO₂)

Pearl necklace

Pearl: biogenic calcium carbonate, primarily aragonite (CaCO₃), in a conchiolin matrix

Chert (or possibly Flint)

SiO2 (Silicon Dioxide)

Calcite

Calcite (CaCO3)

Seashell fragment

Calcium carbonate (CaCO3)

Kidney Stone (Medical Specimen)

Calcium oxalate monohydrate (Whewellite) / CaC2O4·H2O

Popcorn

Zea mays everta (P. Wilson) (Botanical name for the corn variety)

Coral limestone / fossil coral

Biogenic calcium carbonate, chiefly aragonite or calcite (CaCO₃); likely fossilized colonial coral

Fossilized cylindrical shell or bone fragment

Indeterminate biogenic carbonate or phosphatic fossil; possible fragment of a tubular shell (e.g., scaphopod) or hollow bone

Fossil-bearing concretion, possibly containing a fossil shell or other organic inclusion

Calcareous concretion; exact fossil and host-rock composition are not identifiable from the image

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

Sandstone or Siltstone

Arenite (if sandstone)

Sandstone

Arenite

Shale

Shale (clastic sedimentary rock)

Shale (or Mudstone/Siltstone)

Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)

Quartz pebble

Silicon dioxide (SiO2)

Sedimentary Sandstone

Arenite (Sedimentary Rock)