Chert / Flint (with Crinoid Stem Molds)
Microcrystalline Quartz (SiO2)
sedimentary
Category
Limestone
Browse limestone specimens identified by the Rock Identifier community.
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary
Celestite Geode
Celestine (Strontium Sulfate, SrSO4)
mineral
Piddock bored rock (Boring Stone)
Ichnofossil-bearing Limestone or Mudstone (trace fossils by Pholadidae)
sedimentary
Septarian Nodule (Yellow Jasper variety)
Septarian Nodule (comprising Calcite, Aragonite, and Limestone/Bentonite)
sedimentary
Coquina
Bioclastic Limestone (composed primarily of Calcium Carbonate / CaCO3)
sedimentary
Septarian Nodule (Dragon Stone)
Septarian Concretion (CaCO3 - Calcite, Aragonite, and Limestone/Clay)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
sedimentary
Quartzite (or Milky Quartz pebble)
Quartzite (primarily Silicon Dioxide, SiO2)
metamorphic
Calcite
Calcite (CaCO3)
Mineral
Chert (variations include Flint or Jasper)
Silicon Dioxide (SiO2)
sedimentary
Lapis Lazuli
Lapis Lazuli (Aggregate of Lazurite (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2, Pyrite, and Calcite)
metamorphic
Chert / Flint Nodules in Sandstone
Microcrystalline Quartz (SiO2) within Clastic Sedimentary Rock
sedimentary
Nephrite Jade
Ca2(Mg, Fe)5Si8O22(OH)2 (Magnesium-rich Tremolite-Actinolite)
metamorphic
Banded Chert in Matrix
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Common Opal/Jasper variety)
Silicon Dioxide (SiO2)
sedimentary
Chert (and Chalcedony/Agate mixture)
Microcrystalline Quartz (SiO2)
sedimentary
Epidote
Epidote (Ca2(Al,Fe)3(SiO4)3(OH))
mineral
Granite (Background) and Quartzite/River Pebble (Foreground Heart)
Phaneritic Felsic Igneous Rock (Granite background)
igneous
Chert (Grey-Green Flint)
Microcrystalline silicon dioxide (SiO2)
sedimentary
Chert (Smooth River Pebble)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Fluorite
Fluorite (Calcium Fluoride, CaF2)
mineral
Fluorite (Purple variety)
Calcium Fluoride (CaF2)
mineral
Iron Slag
Ferrous Slag (complex silicate and oxide byproduct)
industrial byproduct (anthropogenic)
Geode with Iron-Stained Quartz/Calcite
Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3) in Sedimentary Matrix
sedimentary
Chert (specifically Tan/Yellow Chert)
Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)
sedimentary
Nephrite Jade (River Cobble)
Nephrite (Silicate mineral: Ca2(Mg, Fe)5Si8O22(OH)2)
metamorphic
Slag (Industrial Glassy Byproduct)
Ferro-silicate Slag
Anthropogenic / Non-Natural
Barite Rose on Marcasite
Barium Sulfate (BaSO4) on Iron Sulfide (FeS2)
mineral
Quartz Geode
Silicon Dioxide (SiO2) within a secondary sedimentary structure
sedimentary
Fluorite (Rainbow Fluorite)
Calcium Fluoride (CaF2)
mineral
Chert (or possibly Flint)
Chert (variant: Flint)
Sedimentary
Fluorite
Calcium Fluoride (CaF2)
mineral
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Quartz Geode
Quartz (Silicon Dioxide - SiO2) within a Chalcedony and Limonite shell
sedimentary
Agate (specifically, a slice of a Blue Lace or Chalcedony Agate nodule)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Brecciated Jasper
Silicon Dioxide (SiO2) with varying mineral inclusions (Iron Oxide, Hematite, Clay)
sedimentary (clastic/chemical)
Chert (White/Light Tan)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Emerald
Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities
mineral
Green Fluorite
Calcium Fluoride (CaF2)
mineral
Chert (or Flint)
SiO2 (predominantly microcrystalline quartz)
Sedimentary