Bivalve Fossil (Internal Mold/Steinkern)
Class Bivalvia (Fossilized Mold)
sedimentary
Category
Organic (Often Found By Beachcombers)
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Coquina / Shell Limestone
Coquina (Bioclastic Limestone)
sedimentary
Chert (Hag Stone / Hole Stone)
Chert (Cryptocrystalline variety of Quartz, SiO2)
sedimentary
Banded Agate (specifically Moss Agate or Plume Agate variety)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Chert (Jasper/Flint variant)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Fossil Coral (Favosites)
Favosites (Order: Tabulata, Phylum: Cnidaria)
sedimentary
Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite organic gemstone
mineral
Baltic Amber
Succinite (Polmerized conifer resin)
mineraloid
Chert (Jasper/Flint variant)
Silicon Dioxide (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Chert (variations include Flint or Jasper)
Silicon Dioxide (SiO2)
sedimentary
Chert (specifically as a lithic artifact/projectile point)
Chert (Silicon dioxide, SiO2)
sedimentary
Mother of Pearl (Nacre)
Calcium Carbonate (primarily aragonite, with conchiolin)
Organic Gemstone/Biomineral
Fossiliferous Limestone (containing Brachiopods)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Amber
Succinite (a fossilized organic resin containing succinic acid)
mineraloid
Amethyst Sage Agate
Silicon Dioxide (SiO2) with trace minerals (Manganese/Iron oxides)
mineral
Ambergris
Ambrein (C30H52O)
mineraloid / organic geological substance
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary
Pearl (Biogenic Mineraloid)
Calcium carbonate (Aragonite) and Conchiolin, CaCO3
mineral
Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock exposed to metamorphic heat/pressure; Chemical composition is approximately 86%–98% Carbon)
metamorphic
Chert Pebble
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Jasper/Jasperoid)
Chert (chemically precipitated microcrystalline Quartz, SiO2)
sedimentary
Septarian Nodule or Mud Crack Fossil
Septarian Nodule (Concretion)
sedimentary
Tree Agate (or Moss Agate)
Dendritic Agate (Silicon Dioxide - SiO2)
mineral
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Fossiliferous Limestone
CaCO3 (principally Calcite or Aragonite)
sedimentary
Chert (Iron-stained)
Chert (Microcrystalline and Cryptocrystalline Quartz, SiO2)
sedimentary
Chert (with Quartz Veining)
Microcrystalline silicon dioxide (SiO2)
sedimentary
Chert
Chert (SiO2)
sedimentary
Chert (Jasper/Flint variety)
Silicon Dioxide (SiO2)
sedimentary
Pearl (with Peridot)
Calcium carbonate (CaCO3) + Conchiolin; Peridot: Magnesium iron silicate (Mg, Fe)2SiO4
mineral
Unknown Organic Object (likely a berry or fruit)
Not applicable; this is not a geological specimen. If it were a cranberry, its scientific name would be Vaccinium macrocarpon; if a cherry, it would be Prunus avium or Prunus cerasus.
Organic Material (likely a fruit or berry)
Wood Jasper
Siliceous sedimentary rock (variety of Chert/Chalcedony)
Sedimentary
Mookaite Jasper
Silicified Radiolarite (SiO2)
sedimentary
Red Jasper
Jasper (Silicon Dioxide with Iron inclusions - SiO2)
Sedimentary/Metamorphic
Coquina
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Green Jasper (with Quartz veining)
Jasper (Silica-rich microcrystalline variety of Quartz), formula: SiO2
sedimentary
Chert (Arrowhead Preform or Flake)
Microcrystalline Quartz (SiO2)
sedimentary
Graphite
Graphite (Chemical Formula: C)
Mineral (Native Element)
Chert (White-Tan variety)
Silicon dioxide (SiO2) / Microcrystalline Quartz
sedimentary