Pyrite
Iron Sulfide (FeS2)
Category
Browse organic (pseudo geological) specimens identified by the Rock Identifier community.
Pyrite
Iron Sulfide (FeS2)
Blue Apatite
Apatite group (Ca5(PO4)3(F,Cl,OH))
Pyrite
Iron Sulfide (FeS2)
Freshwater Pearl
Aragonite / Biogenic Calcium Carbonate (CaCO3)
Likely coal (possibly anthracite)
Coal, composed chiefly of carbon-rich organic matter; rank cannot be confirmed from the photograph
Red Coral (Precious Coral)
Corallium rubrum (Calcium Carbonate, CaCO3)
Pearls (likely freshwater cultured pearls)
Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin
Chert
Chert (SiO2)
Limestone (or Calcite Pebble)
Calcium Carbonate (CaCO3)
Chert
Microcrystalline Quartz (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline quartz (SiO2)
Chert Pebble
Microcrystalline Quartz (SiO2)
Banded Chert
Silicon Dioxide (SiO2)
Mother of Pearl and Onyx
Aragonite (Mother of Pearl) and Chalcedony (Onyx)
Quartz-veined Limestone
Sedimentary limestone with quartz/calcite veinlets
Fulonite (Fulgurite-like)
Fulgurite (SiO2 fused silica/lechatelierite)
Orbicular granite (likely Rapakivi-type granite)
Granite, chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende
Chert Pebble
Chert (SiO2)
Chert (Flint)
Silicon Dioxide (SiO2)
Chert
Microcrystalline Quartz (SiO2)
Chert (Jasper variation)
Chert (Microcrystalline Silicon Dioxide, SiO2)
Amber
Succinite (Approximate formula: C10H16O)
Black Freshwater Pearls
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
Jasper
Silicon Dioxide (SiO2) with impurities
Chert (Jasper variation)
Silicon Dioxide (SiO2)
Desert Rose Fragment (Atypical) / Weathered Chert
Silicon Dioxide (SiO2) or Barium Sulfate (BaSO4) depending on exact mineralogy
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Chert (Smooth River Pebble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Chalcopyrite
CuFeS2
Glauconitic Sandstone
Glauconitic Quartz Arenite
Chert (specifically Flint or Jasper variant)
Microcrystalline quartz (SiO2)
Chert
Microcrystalline Quartz (SiO2)
Chert
Cryptocrystalline Quartz (SiO2)
Limestone with Fossil Fragment
Sedimentary carbonate rock (CaCO3)
Petrified Wood
Silicified Wood (primarily Quartz / Chalcedony: SiO2)
Ambergris (Geological/Organic Specimen)
Ambra grisea (Produced by Physeter macrocephalus)
Fossilized Plant or Tree Bark
Lepidodendron or Sigillaria (example genera)
Likely bituminous coal
Coal, predominantly carbon-rich organic matter with variable maceral and mineral content
Chert (Jasper/Flint variant)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Chert (Jasper)
Microcrystalline Quartz (SiO2)
Chert (variations include Flint)
Silicon Dioxide (SiO2)
Sandstone
Arenite