Piddock bored rock (likely Mudstone or Shale)
Ichnofossil (Gastrochaenolites borings) in Fine-grained Sedimentary Rock
sedimentary
Category
Marble
Browse marble specimens identified by the Rock Identifier community.
Fossiliferous Limestone
Calcium carbonate (CaCO3) with marine fossils
sedimentary
Fossiliferous Limestone
CaCO3 (principally Calcite or Aragonite)
sedimentary
Chalk
Micrite (primarily Calcium Carbonate or CaCO3)
sedimentary
Peridot (Olivine)
Magnesium Iron Silicate (Mg, Fe)2SiO4
mineral
Marine invertebrate fossils (Brachiopods and Gastropods)
Phylum Brachiopoda and Class Gastropoda
fossil
Crinoid Stalk in Limestone
Crinoid fossil in Biomicrite (Limestone)
sedimentary
Jade (Nephrite or Jadeite)
Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2 - a variety of actinolite, an amphibole mineral); Jadeite (Na(Al,Fe3+)Si2O6 - a pyroxene mineral)
Metamorphic rock (for both Nephrite and Jadeite)
Cupronickel Coin
Copper-Nickel Alloy (typically 75% Cu, 25% Ni)
anthropic metallic specimen
Mosasaur Jaw Fossil in Matrix
Mosasaurus (family Mosasauridae) in Phosphate Sandstone
sedimentary
Peridot
Olivine (Magnesium Iron Silicate), (Mg, Fe)2SiO4
mineral
Eclogite (retrograded)
Eclogite (Omphacite-Garnet rock)
metamorphic
Kimberlite
Kimberlite (Potassic ultramafic igneous rock)
igneous
Fossilized Tabulate Coral
Favosites (Honeycomb Coral)
fossil
Peridot (Olivine)
Magnesium Iron Silicate (Mg, Fe)2SiO4
mineral
Eclogite
Eclogite (Omphacite + Pyrope)
metamorphic
Coralline Algae / Maerl
Lithothamnion (Biogenic Calcium Carbonate)
sedimentary
Olivine in Basalt (Peridotite Xenolith)
Forsterite-rich Olivine (Mg2SiO4) in Aphanitic Basalt
igneous
Basalt with Peridotite Xenolith
Mafic Igneous Rock with Peridotite Inclusion (Olivine-rich)
igneous
Talc
Talc (Mg₃Si₄O₁₀(OH)₂)
Mineral
Diamond in Kimberlite
Diamond in Kimberlite Matrix (Diamond: C, Kimberlite: complex Potassic Peridotite)
igneous
Eclogite
Eclogite (Omphacite-Garnet Metamorphic Rock)
metamorphic
Fossiliferous Limestone (Coral Rag)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Megalodon Tooth
Otodus megalodon
sedimentary
South Korean 100 Won Coin (Cupronickel)
Cupronickel Alloy (75% Cu, 25% Ni)
mineral-based alloy (anthropogenic)
White Coral
Corallium rubrum (biocarbonate calcium) / CaCO3
mineral
Oolitic Limestone / Fossiliferous Chert
Oolitic Limestone (CaCO3) / Silicified Limestone
sedimentary
Fossilized Shark Tooth
Otodus obliquus (Mackerel Shark)
sedimentary
Eclogite
Eclogite (composed primarily of Omphacite and Garnet)
metamorphic
Kimberlite
Kimberlite (Group I or II)
igneous
Fossilized Brachiopod/Bivalve in Limestone
Brachiopoda or Bivalvia fossil in Calcite/Limestone (CaCO3)
sedimentary
Piddock-bored Mudstone
Lutite (Siltstone or Mudstone) with Pholad borings
sedimentary
Echinoid Fossil (Sea Urchin Fossil)
Echinoidea (phylum Echinodermata), often preserved as Calcite (CaCO3)
sedimentary
Megalodon Shark Tooth (Partial Fossil)
Otodus megalodon (fossilized in Calcium Phosphate/Apatite)
Mineral/Fossil
Eclogite
Eclogite (Omphacite + Almandine-Pyrope Garnet)
metamorphic
Rough Diamond
Carbon (C)
mineral
Fossilized Shark Tooth (Scapanorhynchus)
Scapanorhynchus texanus
fossil
Peridot
Olivine ((Mg, Fe)2SiO4)
mineral
Fossilized Shark Tooth
Fossilized elasmobranch tooth (Apatite/Calcium Phosphate)
sedimentary
Olivine-rich Basalt with Peridotite Xenoliths
Porphyritic Basalt containing Dunite/Peridotite (Mg,Fe)2SiO4
igneous
Fossilized Shark Tooth
Fossilized Elasmobranchii tooth (likely Odontaspis or Carcharias)
sedimentary
Peridotite
Ultramafic intrusive rock (Peridotite)
Igneous