Fossil Shell Fragment (possibly Brachiopod or Bivalve)
Calcium Carbonate (CaCO3) - Phylum Brachiopoda or Mollusca
sedimentary
Category
Organic (Often Found By Beachcombers)
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Chert (and Chalcedony)
Silicon Dioxide (SiO2)
sedimentary
Dragon Blood Jasper
Epidote with Red Piedmontite (Chalcedony/Quartz variant)
sedimentary
Pyrite
Pyrite (Iron sulfide, FeS₂)
mineral
Chert (Flint)
Chert (SiO2)
sedimentary
Bituminous Coal (with Anthracite or Vitrinite inclusion)
Organic-rich Sedimentary Rock (Carboniferous classification)
sedimentary
Mother of Pearl (Nacre)
Nacre (Aragonite/Conchiolin), CaCO3 + Organic Polymers
mineral
Moss Agate
Chalcedony (SiO2) with inclusions of manganese or iron oxides
mineral
Chert (and Flint)
Chert (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Chert (Beach Pebble)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (including Flint and Jasper variants)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Travertine (used in construction, not a 'specimen' in situ)
Travertine
Sedimentary
Moss Agate
Silicon Dioxide (SiO2) with Chlorite/Oxide inclusions
mineral
Chert (Flint variety)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Yellow or Brown Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Shungite
Non-crystalline carbon (similar to anthracite coal or meta-anthracite)
metamorphic
Shale
Fissile Mudstone (Shale)
sedimentary
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
sedimentary
Amber
Succinite (Fossilized Tree Resin), C10H16O
Organic Mineraloid
Amber
Succinite (C10H16O)
Mineraloid
Green Moss Agate / Jasper
Silicon Dioxide (SiO2) - Microcrystalline Quartz with Iron and Manganese inclusions
sedimentary
Precious Red Coral
Corallium rubrum / Corallium japonicum
mineral (organic gemstone)
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Turquoise and Red Coral
CuAl6(PO4)4(OH)8·4H2O (Turquoise) and Corallium rubrum (Red Coral)
mineral
Chert (Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Moss Agate
Chalcedony (Silicon Dioxide - SiO2) with inclusions
Mineral
Red Jasper
Silicon Dioxide (SiO2)
sedimentary
Chert / Jasper
Silicon Dioxide (SiO₂)
sedimentary
Shungite
Shungite (carbon-rich Precambrian mineraloid)
mineral
Amber
Succinite (with a generalized formula of C10H16O)
mineral
Amber
Succinite (specifically for Baltic amber); chemical formula approx. C10H16O
Organic Gemstone (fossilized resin)
Sandstone
Arenite
sedimentary
Fossiliferous Limestone (Coquina / Shell Limestone)
Bioclastic Limestone (CaCO3)
sedimentary
Green Moss Agate
Agate (Silicon Dioxide - SiO2 with inclusions of Manganese/Iron oxides)
mineral
Chert (variations include Flint/Jasper)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Bituminous Coal
Organic Sedimentary Rock (Carbon-based)
sedimentary
Chert (varieties include Flint and Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Precious Coral
Corallium rubrum (Calcium carbonate with trace carotene)
Organic gemstone / Sedimentary mineraloid
Coquina or Fossiliferous Limestone
Fossiliferous Calcarenite (CaCO3)
sedimentary
Glauconitic Sandstone
Glauconitic Sandstone (contains (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)
sedimentary
Green Moss Agate
Silicon Dioxide with inclusions (SiO2 + Mn/Fe)
sedimentary