Septarian Nodule
Septarian Concretion (Calcium Carbonate/Aragonite/Calcite)
Category
Browse sedimentary (secondary mineral formation) specimens identified by the Rock Identifier community.
Septarian Nodule
Septarian Concretion (Calcium Carbonate/Aragonite/Calcite)
Milky Quartz
Quartz (Silicon Dioxide - SiO2)
Quartzite (Iron-stained)
Quartzite (mostly SiO2 with Fe2O3 impurities)
Sandstone
Arenite (composed primarily of SiO2)
Ocean Jasper
Orbicular Jasper (variety of Chalcedony - SiO2)
Sandstone (Ferruginous)
Arenite (Fe2O3 staining)
Sandstone
Arenite (primarily SiO2)
Sandstone (Water-worn Pebble)
Clastic Sedimentary Rock (primarily SiO2)
Sandstone (with potential mineral inclusions)
Clastic sedimentary rock (primarily Quartz, SiO2)
Kambaba Jasper
Stromatolite / Fossilized Algae (Rhyolitic structure)
Sandstone Concretion
Clastic Sedimentary Rock (primarily SiO2 with mineral cement)
Sandstone (Ferruginous)
Arenite with Iron Oxides
Green Fluorite
Fluorite (Calcium Fluoride, CaF2)
Sandstone (Yellow/Siltstone variant)
Arenite (SiO2 primarily)
Botryoidal Hematite (Iron Stone Conglomerate)
Hematite (Fe2O3) in sedimentary matrix
Fluorite
Calcium fluoride (CaF2)
Banded Gneiss (River Rock/Pebble)
Gneiss (specifically a banded variety often found as a river rock)
Sandstone
Arenite
Granite Pebble
Intrusive Felsic Igneous Rock (primarily SiO2 with Al2O3, K2O, Na2O)
Pyrite
Iron Sulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)
Pyrite in Matrix (often with Chalcopyrite)
Iron Sulfide (FeS2) / Copper Iron Sulfide (CuFeS2)
Gneiss (specifically a Granitic Gneiss)
Gneiss (Composition: Quartz, Feldspar, Mica)
Granite Cobble
Granite (Phaneritic Quartz-Feldspar Felsic Rock)
Aragonite Star Cluster
Aragonite (Calcium Carbonate, CaCO3)
Mica Schist
Foliated Metamorphic Rock (rich in Muscovite or Biotite)
Black Star Diopside
Diopside (CaMgSi2O6) with Magnetite inclusions
Quartz Geode with Goethite/Hematite
Silicon Dioxide (SiO2) with Iron Oxides
Fluorite
Calcium Fluoride (CaF2)
Opal
Hydrated Silica (SiO2·nH2O)
Shale or Siltstone
Sedimentary Clastic Rock (Variable mineral composition including quartz and clay minerals)
Green Jasper
Silicon Dioxide (SiO2) with mineral inclusions
Sandstone
Arenicola (comprising mostly Quartz, SiO2)
Rough Quartz (Alluvial Pebbles)
Silicon Dioxide (SiO2)
Rutilated Quartz
Quartz (SiO2) with Rutile (TiO2) inclusions
Sandstone
Arenite (SiO2 based)
Metal Alloy (Likely Pewter or Sterling Silver)
Not a natural geological specimen; composed of refined metals. If pewter, it's a tin-based alloy. If sterling silver, it's 92.5% silver and 7.5% other metals (usually copper).
Gneiss (Banded Gneiss)
Gneiss
Pebble (likely Quartz or Chert)
SiO₂ (Silicon Dioxide) - referring to the likely main mineral composition, Quartz. If it's chert, the scientific name remains SiO₂ with a microcrystalline structure.
Sandstone (Quartz-rich)
Arenite (primarily SiO2)
Sandstone (likely Quartz Sandstone)
Arenite (composed primarily of SiO2)
Sandstone (with potential fossil inclusions)
Clastic sedimentary rock (primarily SiO2)