Bituminous Coal
Organic sedimentary rock (humic coal)
Category
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Bituminous Coal
Organic sedimentary rock (humic coal)
Mosasaur Jaw Fossil in Matrix
Mosasaurus (family Mosasauridae) in Phosphate Sandstone
Chert (Iron-rich or Slate-like variant)
Silicon Dioxide (SiO2)
Banded Chert
Microcrystalline Quartz (SiO2)
Chert (Arrowhead/Tool variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Iron-stained)
Microcrystalline quartz (SiO2)
Ironstone Concretion
Goethite-rich Siltstone / Siderite (FeCO3)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Chert (Polished/Tumbled)
Silicon Dioxide (SiO2)
Amber
Succinite (fossilized resin)
River Pebble (Siltstone/Mudstone)
Clastic sedimentary rock
Sandstone (likely Arkose or Quartz Sandstone)
Arenite (SiO2 principal component)
Chert (Gravel)
Microcrystalline Quartz (SiO2)
Chert / Flint
Silicon dioxide (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Chert (Flint)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Amber with inclusion
Amber (Fossilized Tree Resin)
Pyrite (Pseudomorph)
Iron Sulfide (FeS2)
Chert
Chert (Microcrystalline Quartz, SiO2)
Ferruginous Quartz
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
Chert (specifically Black Chert or Flint)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Chert (Jasper/Flint variant)
Silicon Dioxide (SiO2)
Chert (and Limestone)
Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3)
Chert (Iron-stained variant)
Microcrystalline Quartz (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Jasper with Agate and Quartz Inclusions
Silicon Dioxide (SiO2) - Chalcedony / Quartz aggregate
Banded Chert
Microcrystalline Quartz (SiO2)
Chert (with Limestone matrix)
Chert (Silica: SiO2)
Chert (Basanite / Flint variety)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2 as Quartz/Chert/Chalcedony)
Chert (Yellow Jasper/Flint)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Fossilized Shark Tooth
Carcharhinus sp. (likely Bull or Requiem shark family)
Pyrite Geode (Sparkling Druzy)
Iron Sulfide (FeS2) in Sedimentary Nodule
Glauconitic Sandstone
Glauconitic Quartz Sandstone (K(Fe,Al)2(Si,Al)4O10(OH)2)
Chert / Flint
Microcrystalline Quartz (SiO2)
Chert (Yellow Jasper variant)
Silicon Dioxide (SiO2)
Chert (Flint)
Silicon Dioxide (SiO2)
Chert (and Flint)
Silicon Dioxide (SiO2) - Microcrystalline Quartz