Coquina
Biogenic Limestone (Calcite/Aragonite)
Category
Browse anthropogenic (man made material processed by nature) specimens identified by the Rock Identifier community.
Coquina
Biogenic Limestone (Calcite/Aragonite)
Petrified Wood
Silicified Wood (SiO2)
Scoria (Volcanic Rock)
Scoria (often basaltic scoria)
Sandstone (Graywacke type)
Clastic Sedimentary Rock (Lithic Sandstone)
Coral Rock (Coquina)
Biogenic Limestone (Calcium Carbonate - CaCO3)
Chert (often called Flint or Agate nodule)
Cryptocrystalline Quartz (SiO2)
Bituminous Coal (with Anthracite or Vitrinite inclusion)
Organic-rich Sedimentary Rock (Carboniferous classification)
Clay (as a rock-forming material)
Clay minerals (e.g., Kaolinite group, Smectite group, Illite group, Chlorite group)
Gold Nugget
Native Gold (Au)
Tufa
Calcareous Tufa (CaCO3)
Jasper (Iron-rich Chalcedony)
Jasper (Microcrystalline Silicon Dioxide, SiO2 plus iron oxide impurities)
Sandstone
Arenite (composed primarily of SiO2)
Coquina
Biogenic Limestone
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Painted Pet Rock (Quartzite/Sandstone base)
Silicon Dioxide (SiO2) with anthropomorphic acrylic embellishments
Blue Goldstone
Aventurine Glass (Silicon Dioxide infused with Cobalt/Copper)
Granite Cobble/Pebble
Granite
Sea Glass (Uranium/Vaseline Glass variant)
Silicon Dioxide (SiO2) with trace Uranium Oxide (U3O8)
Goldstone
Not a natural mineral or rock. It is an ornamental glass.
Obsidian
Obsidian (volcanic glass, amorphous silica rich rock)
Quartz (Engineered Quartz Surface)
Silicon Dioxide (SiO2) based composite
Picture Jasper
Silicon Dioxide (SiO2) with mineral inclusions
Shale or Argillite
Shale (sedimentary) / Argillite (metamorphic)
Rough Citrine Quartz
Citrine (Silicon Dioxide, SiO2 with iron impurities)
Nickel coin (U.S. currency)
Cupronickel (75% Copper, 25% Nickel alloy)
Jasper
Silicon Dioxide (SiO2)
Coquina / Shell Limestone
Coquina (Bioclastic Limestone)
Sandstone
Arenite (primarily SiO2)
Sandstone (Ferruginous)
Arenite with Iron Oxide cement (primarily SiO2 with Fe2O3)
Dyed Quartz (often sold as 'Blue Quartz' or 'Blue Agate')
Silicon Dioxide (SiO2) with artificial pigment
Silicon Carbide (Carborundum)
Silicon Carbide (SiC)
Milky Quartz
Silicon Dioxide (SiO2)
Diorite (Gneissic)
Diorite
Dyed Agate
Silicon Dioxide with artificial pigment (SiO2)
Chert (and/or Flint)
Chert (Cryptocrystalline variety of Quartz, SiO2)
Chert (and associated river cobbles)
Silicon dioxide (SiO2)
Fossiliferous Limestone
Limestone (composed primarily of calcite with included fossils CaCO3)
Banded Sandstone
Arenite with Liesegang banding
Chipped Glass/Plastic Fragment
Silicon dioxide (SiO2) for glass (amorphous) or various polymer compounds for plastic
Jasper
Jasper (Silicon Dioxide, SiO2)
Fossilized Coral (Coquina/Limestone)
Cnidaria Anthozoa (Fossilized)
Graphite-veined Quartzite
Meta-sedimentary Quartzite with Carbonaceous/Graphitic Inclusions (SiO2 + C)