Pearl (Biogenic Mineraloid)
Calcium carbonate (Aragonite) and Conchiolin, CaCO3
mineral
Category
Organic (Often Found By Beachcombers)
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Learn about Organic (Often Found By Beachcombers) in the encyclopedia
View all →
Fossiliferous Limestone (containing Brachiopods)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Amethyst Sage Agate
Silicon Dioxide (SiO2) with trace minerals (Manganese/Iron oxides)
mineral
Petrified Wood
Silicified Wood (SiO2)
mineral
Mother of Pearl (Nacre)
Calcium Carbonate (primarily aragonite, with conchiolin)
Organic Gemstone/Biomineral
Tree Agate (or Moss Agate)
Dendritic Agate (Silicon Dioxide - SiO2)
mineral
Fossilized Shark Tooth
Elasmobranchii fossil (likely Odontaspididae family)
sedimentary
Chert (Jasper/Jasperoid)
Chert (chemically precipitated microcrystalline Quartz, SiO2)
sedimentary
Chert Pebble
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary
Blue Quartzite (Dyed)
Metamorphosed Quartz-rich Sandstone (SiO2 with organic dye)
metamorphic
Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock exposed to metamorphic heat/pressure; Chemical composition is approximately 86%–98% Carbon)
metamorphic
Septarian Nodule or Mud Crack Fossil
Septarian Nodule (Concretion)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
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
Wood Jasper
Siliceous sedimentary rock (variety of Chert/Chalcedony)
Sedimentary
Gastropod Steinkern (Fossil Snail Internal Mold)
Class Gastropoda (Internal Mold)
sedimentary
Petrified Wood
Silicified wood (Quartz/Chalcedony/SiO2)
sedimentary
Green Jasper (with Quartz veining)
Jasper (Silica-rich microcrystalline variety of Quartz), formula: SiO2
sedimentary
Pearl (with Peridot)
Calcium carbonate (CaCO3) + Conchiolin; Peridot: Magnesium iron silicate (Mg, Fe)2SiO4
mineral
Coquina
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Mookaite Jasper
Silicified Radiolarite (SiO2)
sedimentary
Slate
Slate (Foliated metamorphic rock)
metamorphic
Amber with Inclusion
Succiniferous fossil resin (C10H16O)
mineraloid
Turquoise and Red Coral
Turquoise: CuAl6(PO4)4(OH)8·4H2O; Red Coral: Corallium rubrum (organic gemstone)
mineral
Chert (Yellow Jasper variant)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Arrowhead Preform or Flake)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (White-Tan variety)
Silicon dioxide (SiO2) / Microcrystalline Quartz
sedimentary
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Graphite
Graphite (Chemical Formula: C)
Mineral (Native Element)
Fossilized Coral
Scleractinia (fossil order), primarily Calcium Carbonate (CaCO3)
sedimentary
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Red Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Red Jasper
Jasper (Silicon Dioxide with Iron inclusions - SiO2)
Sedimentary/Metamorphic
Lepidolite
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)
mineral
Petrified Wood
Silicified Wood (primarily Quartz / Chalcedony: SiO2)
metamorphic