Orthoceras Fossil Limestone
Orthoceras (extinct Cephalopod fossil) in Matrix
sedimentary
Category
Mineral (Silicate Replaced Organic Material)
Browse mineral (silicate replaced organic material) specimens identified by the Rock Identifier community.
Limonite (Iron Ore)
Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)
mineral
Chert Pebble (Jasper variant)
Microcrystalline Quartz (SiO2)
sedimentary
Pyritized Ammonite
Ammonitida (replaced by Iron Disulfide, FeS2)
sedimentary
Olivine (Peridotite)
Magnesium iron silicate (Mg, Fe)2SiO4
igneous
Chert (Flint variety)
Microcrystalline Quartz (SiO2)
sedimentary
Unakite
Epidotized Granite
metamorphic
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Pearl and Garnet Glass
Calcium Carbonate (CaCO3) for pearl; Silicon Dioxide (SiO2) for glass
mineral and glass
Fossilized Sea Urchin (Echinoid)
Echinoidea (Fossil specimen, often replaced by Calcite or Silica)
sedimentary
Olivine (Peridot)
Magnesium Iron Silicate (Mg,Fe)2SiO4
Mineral
Chert (often colloquially called Flint)
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Amber
Succinite (specifically for Baltic Amber), Formula: C10H16O
Mineraloid
Petrified Wood
Silicified Wood (SiO2)
mineral
Petrified Wood (Agatized/Silicified Wood)
Silicified Wood (SiO2 - Silicon Dioxide)
metamorphic
Sandstone (with Iron Oxide staining)
Arenite (primarily SiO2 with Fe2O3 staining)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Unakite
Epidotized Granite
metamorphic
Unakite
Epidotized Granite
metamorphic
Chert (Nodule)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Unakite
Unakitized granodiorite / Quartz-Epidote-Feldspar rock
metamorphic
Unakite
Epidotized Granite (SiO2, KAlSi3O8, Ca2(Al, Fe)3(SiO4)3(OH))
metamorphic
Jasper
Silicon dioxide (SiO2)
sedimentary
Olivine (Peridot in gem form)
Magnesium Iron Silicate (Mg,Fe)2SiO4
mineral
Jasper
Silicon dioxide (SiO2)
Mineral
Olivine (Peridot)
Magnesium Iron Silicate (Mg,Fe)2SiO4
mineral
Stardust (Micrometeorite)
Chondrite / Micrometeorite (Extraterrestrial Silicate)
igneous
Fossilized Shark Teeth
Carcharhiniformes or Lamniformes species (common mineral: Fluorapatite/Ca5(PO4)3F)
sedimentary (fossilized organic matter)
Peridot (Olivine)
Olivine (Magnesium Iron Silicate - (Mg, Fe)2SiO4)
mineral
Quartzite
Quartzite (primarily SiO2)
metamorphic
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Yellow Jasper (Mookaite style)
Silicon Dioxide (SiO2) with Goethite/Hematite inclusions
sedimentary
Sandstone (Ferruginous)
Arenite with Iron oxide staining (SiO2 with Fe2O3)
sedimentary
Slag (Industrial Byproduct)
Ferrous/Non-ferrous Silicate
igneous (artificial/anthropogenic)
Geode (unopened)
Chert / Chalcedony Geode (SiO2)
sedimentary
Moss Agate
Chalcedony (Silicon Dioxide - SiO2) with inclusions
Mineral
Chert (varietal Flint)
Silicon Dioxide (SiO2)
sedimentary
Jasper
Silicon dioxide (SiO2)
sedimentary
Olivine (Peridot)
Magnesium Iron Silicate (Mg,Fe)2SiO4
mineral
Leopard Skin Jasper
Orbicular Rhyolite (Silicon Dioxide with various impurities)
sedimentary
Ironstone Concretion (Iron-rich Mudstone)
Siderite / Geothite concretion (FeCO3 / FeO(OH))
sedimentary