Possible fossilized ammonite or concretion
Indeterminate fossil specimen; possibly an ammonoid mold/cast in iron-rich sedimentary rock
Category
Browse organic (non geological) specimens identified by the Rock Identifier community.
Possible fossilized ammonite or concretion
Indeterminate fossil specimen; possibly an ammonoid mold/cast in iron-rich sedimentary rock
Fossiliferous Brachiopod in Shale
Brachiopoda (Phylum) preserved in Carbonaceous Shale
Jasper
Jasper (Silicon Dioxide, SiO2)
Green Jasper (with Quartz veining)
Jasper (Silica-rich microcrystalline variety of Quartz), formula: SiO2
Banded Chert
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Chert (White/Light Tan)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Nodular)
Chert (SiO2 - Microcrystalline Quartz)
Chert Pebble with Quartz Veins
Microcrystalline Quartz (SiO2)
Chert (specifically Tan/Brown Chert)
Chert (SiO2)
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (mostly SiO2)
Black Obsidian
Volcanic Glass (predominantly SiO2, Silicon Dioxide)
Obsidian
Volcanic Glass (predominantly SiO2 – Silicon Dioxide, but non-crystalline)
Chert (Jasper variation)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Obsidian
Volcanic glass (Mainly SiO2)
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)
Travertine (Tufa)
Chemical Limestone (CaCO3)
Petrified Wood
Silicified Wood (primarily Quartz / Chalcedony: SiO2)
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
Quartz Geode in Chert/Limestone Matrix
Silicon Dioxide (SiO2) within Sedimentary Host Rock
Chert (Septarian or Nodular variety)
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Limestone (Weathered)
Calcium Carbonate (CaCO3)
Obsidian
Volcanic Glass (70-75% SiO2 with MgO and Fe3O4)
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide and organic impurities
Chert (and Jasper variety)
Microcrystalline Quartz (SiO2)
Quartzite
Metamorphic Quartzite (SiO2)
Coquina / Shelly Sandstone
Calcareous Sandstone / Coquina
Quartzite
Metamorphic Quartzite (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Petrified Wood
Silicified Wood (SiO2 - primarily Quartz/Chalcedony/Opal)
Fancy Jasper (Agate/Chert mix)
Silicon Dioxide (SiO2) with impurities
Yellow Chert
Sedimentary cryptocrystalline quartz (SiO2)
Chert (Chert Nodule)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Iron-stained River Cobble)
Microcrystalline Quartz (SiO2)
Graphite
Graphite (C)
Red Siltstone (or Red Shale)
Clastic Sedimentary Rock (Composition: primarily Quartz, Clay minerals, and Hematite Fe2O3)
Red Jasper
Silicon dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions
Septarian Nodule
Septarian Concretion (CaCO3 with Siderite/Calcite/Aragonite)
Chert (often called Flint when found in chalk/limestone)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Apache Tear
Obsidian (Hydrated Volcanic Glass - SiO2)
Chert (Flint)
Silicon Dioxide (SiO2)