Limestone with Calcite Veins
Calcium Carbonate (CaCO3)
sedimentary
Category
Organic (Often Found By Beachcombers)
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Sandstone
Arenicola (comprising mostly Quartz, SiO2)
sedimentary
Pearl
Organic gemstone (Calcium carbonate - CaCO3)
mineral
Anthracite Coal
Anthracite (Carbon based fossil fuel)
metamorphic
Fancy Jasper
Silicon dioxide (SiO2)
sedimentary
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary
Amber
Succinite (organic mineraloid); Chemical formula: C10H16O
mineral
Fossiliferous Limestone (Coquina)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Ambergris (Sea Wax)
Physeter macrocephalus fecalith
Organic geological/oceanic specimen
Ammonite Fossil
Ammonoidea (Calcium carbonate - CaCO3)
sedimentary
Petrified Wood
Silicified Wood (primarily Chalcedony/Quartz, SiO2)
sedimentary
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Jasper (specifically Polychrome or Desert Jasper)
Silicon Dioxide (SiO2) with iron oxide and other mineral impurities
sedimentary (chemical/biological origin)
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
sedimentary
Jasper with Quartz Vein
Silicon Dioxide (SiO2) with impurities
sedimentary
Chert (Flint variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Red Jasper
Quartz (Silicon Dioxide) with Hematite inclusions, SiO2
mineral
Chert with Iron Staining
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood / Chalcedony (SiO2)
mineral
Chert (Jasper variety)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Chert (Yellow Jasper variant)
Microcrystalline Quartz (SiO2)
sedimentary
Amber
Succinite (specifically Baltic Amber) - Formula: C10H16O (approximate)
Organic Mineraloid
Chert / Flint (with Crinoid Stem Molds)
Microcrystalline Quartz (SiO2)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Amber (and Citrine Quartz)
Succinite (Amber) and Silicon Dioxide (SiO2)
Organic Mineraloid and Mineral
Coquina Limestone (Fossiliferous Limestone)
Calcareous bioclastic sedimentary rock (CaCO3)
sedimentary
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Petrified Wood (Silicified Wood)
Silicified Wood / Silicon Dioxide (SiO2)
metamorphic
Chert (varieties: Flint or Chalcedony)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Gravel specimen)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (with Quartz Veining)
Chert (formula: SiO2)
sedimentary
Chert (specifically Jasper/Flint pebble)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Banded Chert
Cryptocrystalline Quartz (SiO2)
sedimentary
Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxides
Mineral (Variety of Chalcedony)
Chert (Jasper/Flint variant)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Coral (Precious Coral)
Corallium rubrum (Red Coral), Paracorallium japonicum (Momo Coral), Pleurocorallium elatius (Sardinian Coral), various other species within the Corallidae family. Chemically, it's primarily Calcium Carbonate (CaCO 3 ).
Mineral, Organic Gemstone
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Limestone (specifically Fossiliferous or Crinoidal Limestone)
Calcium Carbonate (CaCO3) - Calcite Rock
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Turquoise and Spiny Oyster (Heishi style beads)
Turquoise (CuAl6(PO4)4(OH)8·4H2O) and Spondylus (Spiny Oyster shell)
mineral and organic gemstone
Jasper
Silicon dioxide (SiO2)
sedimentary
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
sedimentary