Sandstone
Sandstone (principally SiO2)
sedimentary
Category
Organic Gemstone (Fossilized Resin)
Browse organic gemstone (fossilized resin) specimens identified by the Rock Identifier community.
Learn about Organic Gemstone (Fossilized Resin) in the encyclopedia
View all →
Chert (Yellow Jasper variant)
Silicon Dioxide (SiO2)
sedimentary
Terrazzo (Man-made Composite)
Cementitious or Resin-bound Lithic Composite
sedimentary (artificial)
Fossilized Brachiopod in Limestone
Phylum Brachiopoda embedded in sedimentary limestone
fossil
Fossil Coral and Quartz Pebble
Fossilized Anthozoa / Silicon Dioxide (Quartz)
sedimentary
Pink Opal
Hydrated Silica (SiO2·nH2O) with Palygorskite/Sepiolite inclusions
gemstone
Moss Agate
SiO2 (Cryptocrystalline Quartz)
gemstone
Petoskey Stone
Hexagonaria percarinata
fossil
Chert Nodules (with Gryphaea or Shell inclusions)
Microcrystalline Quartz (SiO2) with Calcitic inclusions
sedimentary
Chert (specifically Flint or Dark Chert)
Chert (SiO2)
sedimentary
Black Pearl (Tahitian-style Cultured Pearl)
Calcium Carbonate (Aragonite) with Conchiolin (CaCO3)
mineral
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary
Red Chert
Microcrystalline Quartz (SiO2)
sedimentary
Precious Coral
Corallium rubrum (Calcium carbonate with trace carotene)
Organic gemstone / Sedimentary mineraloid
Honey-colored chalcedony (likely carnelian)
Microcrystalline quartz, SiO₂; orange chalcedony colored by iron oxides
mineral
White seed-bead gemstone strand, likely freshwater pearl or shell pearl
Pearl: nacreous calcium carbonate, chiefly aragonite (CaCO₃) in conchiolin; identification uncertain from image
gemstone
Fossiliferous Chert or Limestone
Sedimentary rock containing fossilized marine invertebrates (likely crinoid stems or bryozoans)
sedimentary
Pearl
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
mineral
Chert (often called Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Moss Agate
Cryptocrystalline Quartz (SiO2 with Manganese or Iron Oxide inclusions)
mineral
Fulgarite
Fulgurite (Lechatelierite / Vitrified Sand)
igneous
Bituminous Coal
Coal (Sedimentary Rock)
sedimentary
Crinoid Stem Fossil
Crinoid ossicle (phylum Echinodermata)
fossil
Fossil Coral
Hexagonaria or Rugose coral fossil in limestone/silica matrix
fossil
Petrified Coral Fossil
Rugose or Tabulate Coral (Hexagonaria or similar fossilized cnidarian)
fossil
Hard Sandstone (Quartzite)
Quartz-rich Sedimentary Rock (Proto-Quartzite)
metamorphic
Crinoid Stem Fossil
Crinoid Columnal (Phylum Echinodermata)
fossil
Sandstone
Arenite (SiO2 primarily)
sedimentary
Zebra Rock (Zebra Stone / Ribbon Stone)
Siltstone with Ferruginous Banding (Primarily Quartz, Kaolinite, and Hematite)
sedimentary
Fossilized Coral (Petoskey Stone or similar Favosites)
Hexagonaria percarinata / Favosites (Silurian-Devonian Coral)
sedimentary
Jasper
Silicon dioxide (SiO2)
sedimentary
Jasper
Silicon Dioxide (SiO2) with impurities
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Iron inclusions
sedimentary
Crinoidal Limestone
Bioclastic Limestone
Sedimentary
Elephant Skin Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (specifically Brown Chert or Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (White Flint)
Silicon Dioxide (SiO2)
sedimentary
Quartz (Engineered Stone Countertop)
Silicon Dioxide (SiO2) with polymer resins
Sedimentary-like (Industrial Composite)
Petoskey Stone
Hexagonaria percarinata
sedimentary
Fossilized Shark Tooth
Chondrichthyes (Class)
fossil
Shark Tooth Fossil
Lamniformes (Shark tooth fossil composed of Fluorapatite)
fossil