Silicified Snail Fossil
Gastropod (likely replaced by Chalcedony/Quartz - SiO2)
Category
Browse sedimentary (with some aspects of mineral replacement) specimens identified by the Rock Identifier community.
Silicified Snail Fossil
Gastropod (likely replaced by Chalcedony/Quartz - SiO2)
Flint
SiO2 (Microcrystalline Quartz / Chert)
Flint
SiO2 (Cryptocrystalline Quartz)
Flint
SiO2 (Microcrystalline Quartz / Chert)
Flint
Microcrystalline quartz (SiO2)
Chert / Flint
Silicon Dioxide (SiO2)
Chert / Jasper
Silicon Dioxide (SiO2)
Flint (Chert)
Silicon dioxide (SiO2) - Cryptocrystalline Quartz
Chert (or Jasper)
Microcrystalline Quartz (SiO2)
Chert (Chalcedony/Common Opal)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert / Jasper
Cryptocrystalline Quartz (SiO2)
Siderite Concretion
Ironstone (Siderite) Concretion, FeCO3
Ironstone Concretion (Limonite/Goethite)
Ferruginous Sandstone or Limonite (FeO(OH)·nH2O)
Chert (specifically Jasper/Carnelian Agate)
Microcrystalline Quartz (SiO2)
Gneiss
Gneiss (High-grade metamorphic rock)
Quartz Geode
Silicon Dioxide (SiO2)
Tumbled yellow jasper (likely serpentine or calcite-rich stone)
Jasper: microcrystalline quartz (SiO₂); exact yellow veining may indicate serpentine, calcite, or iron oxides
Jasper (Brown Iron-Rich Variety)
Silicon Dioxide (SiO2) with Fe2O3 (Iron Oxide/Crystalline Quartz)
Banded Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Gneiss
Gneiss
Gneiss
Gneiss
Flint
Cryptocrystalline quartz (SiO2)
Flint / Chert
Silicon dioxide (Microcrystalline quartz, SiO2)
Flint
SiO2 (Cryptocrystalline Quartz)
Flint
SiO2 (Microcrystalline Quartz / Chert)
Black Flint
Chert (Microcrystalline Quartz, SiO2)
Magnetite (Iron Ore)
Magnetite (Fe3O4)
Quartz
Quartz (SiO2 - Silicon Dioxide)
Gneiss
Gneiss (High-grade Metamorphic Rock)
Fossilized Coral
Anthozoa (Fossilized)
Gneiss (specifically Epidote-Quartz Gneiss)
Gneiss containing Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)) and Quartz (SiO2)
Botryoidal Chalcedony (Quartz Var.)
Silicon Dioxide (SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
Fossil Shark Tooth
Selachii fossil
Sandstone (Pebble)
Sandstone (SiO2 with iron oxide impurities)
Megalodon Shark Tooth Fossil
Otodus megalodon (fossilized in sedimentary matrix)
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Sandstone
Sandstone (clastic sedimentary rock, predominantly SiO2)
Iron Concretion
Ferruginous concretion (Fe2O3·nH2O / FeO(OH))
Quartz Geode
Silicon Dioxide (SiO2) in Calcareous or Siliceous Matrix
Fossilized Coral
Hexagonaria (Rugose and Tabulate coral fossils)