Seashell Fossil
Gastropoda fossil
Category
Browse organic gemstone (not a rock) specimens identified by the Rock Identifier community.
Seashell Fossil
Gastropoda fossil
Asphalt aggregate
Human-made bituminous asphalt containing crushed silicate rock aggregate
Coal
Bituminous Coal / Anthracite
Starfish Fossil
Asteroidea fossil
Limestone Pebble
Sedimentary Rock (Calcite, CaCO3)
Chert (often called Flint)
Microcrystalline Quartz (SiO2)
Chert (Yellow or Brown Jasper)
Microcrystalline Quartz (SiO2)
Pearl
Nacre (aragonite, CaCO₃, in a conchiolin matrix)
Glauconitic Sandstone
Glauconitic Sandstone with high Glauconite concentration ((K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)
Amber (specifically Red or Cherry Amber)
Succinite (Resinite); Chemical formula: C10H16O
Chert (White Flint)
Silicon Dioxide (SiO2)
Shale or Slaty Mudstone
Argillaceous sedimentary rock
Pearl
Calcium Carbonate (Aragonite/Calcite mixed with Conchiolin), CaCO3
Amber
Succinite
Sandstone
Sandstone (Quartz-rich Arenite / SiO2)
Pink Coral
Corallium rubrum (or related species, composed of calcium carbonate)
Fossilized coral (likely honeycomb or branching coral)
Fossil coral; probable Scleractinia or Tabulata, composition mainly microcrystalline CaCO₃
Chert (Jasper type)
Microcrystalline Quartz (SiO2)
Black Pearl (Tahitian Type)
Aragonite / Pinctada margaritifera (CaCO3 + Conchiolin)
Natural Freshwater Pearl
Calcium Carbonate (Aragonite and Calcite), CaCO3
River Cobble (Sandstone)
Arenite (primarily SiO2)
Amber
Succinite (Approximate formula: C10H16O)
Poppy Jasper
Microcrystalline Quartz (SiO2) with mineral inclusions
Chert (Iron-stained)
Microcrystalline silica (SiO2) with trace Iron oxide (Fe2O3)
Chert Nodules in Limestone
Microcrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)
Sandstone
Sandstone (principally SiO2/Silicon Dioxide)
Chert (specifically Jasper/Flint)
Microcrystalline Quartz (SiO2)
Chert (and Flint)
Cryptocrystalline Quartz (SiO2)
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Amber
Succinite (approximate formula C10H16O)
Amber (Dark/Black Variety)
Succinite (Resinite), C10H16O
Chert (Flint)
Chert (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert (Iron-stained or Dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Granite, possibly granodiorite
Coarse-grained felsic plutonic rock; chiefly quartz (SiO₂), potassium feldspar and plagioclase feldspar, with biotite and/or hornblende
Chert (Jasper transition)
Microcrystalline Quartz (SiO2)
Pearl
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
Pearl
Aragonite / Calcium Carbonate (CaCO3)
Jasper
Silicon dioxide (SiO2)
Jasper
Silicon Dioxide (SiO2) with impurities
Chert (Dark Variety / Flint)
Silicon Dioxide (SiO2)
Chert (Black Chert / Flint)
Silicon Dioxide (SiO2)