Chert (Nodule)
Microcrystalline or Cryptocrystalline Silica (SiO2)
sedimentary
Category
Organic Materia (Not A Rock Or Mineral)
Browse organic materia (not a rock or mineral) specimens identified by the Rock Identifier community.
Learn about Organic Materia (Not A Rock Or Mineral) in the encyclopedia
View all →
Poppy Jasper
Microcrystalline Quartz (SiO2) with hematite and other inclusions
sedimentary
Chert (Nodule)
Chert (composition: SiO2)
sedimentary
Travertine
Calcareous Tufa / Travertine (CaCO3)
sedimentary
Fossilized Brain Coral
Diploria labyrinthiformis (Fossilized)
sedimentary
Septarian Nodule
Septarian Concretion (Calcite, Aragonite, and Limestone)
sedimentary
Mookaite Jasper
Silicified Radiolarite (SiO2)
sedimentary
Petrified Wood
Silicified wood (Quartz/Chalcedony - SiO2)
sedimentary
Amber
Resinite / Fossilized Tree Resin
mineral
Red Coral
Corallium rubrum
mineral
Glauconitic Sandstone (Greensand)
Glauconitic Sandstone ((K, Na)(Fe3+, Al, Mg)2(Si, Al)4O10(OH)2)
sedimentary
Kidney Stone
Nephrolithiasis (Calcium Oxalate, Hydroxyapatite, or Uric Acid)
mineral
Pyritic Mudstone
Argillaceous rock (FeS2)
sedimentary
River Stone (likely Mudstone or Siltstone)
Lutite (Clastic sedimentary rock composed of clay and silt-sized particles)
sedimentary
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement) SiO2
sedimentary
Chert / River Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Polished fossiliferous limestone
Bioclastic carbonate rock, primarily calcite (CaCO₃)
sedimentary
Fossiliferous Siltstone
Clastic Sedimentary Rock with Fossil Inclusions
sedimentary
Fossilized Rugose Coral in Limestone
Order Rugosa in Sedimentary Matrix (CaCO3)
fossil
Amber
Succinite (Fossilized Tree Resin)
mineraloid
Chert (Jasper/Flint variation)
Chert (SiO2)
sedimentary
Tumbled black stone, likely black agate or onyx
Microcrystalline quartz (SiO₂), probably chalcedony/black agate; exact identification requires testing
mineral
White Coral
Corallium rubrum (biocarbonate calcium) / CaCO3
mineral
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Amber cabochon pendant
Amber (fossilized tree resin; chiefly polymerized terpenoids)
gemstone
Fine-grained brown sand or weathered soil
Unconsolidated siliciclastic sediment, likely quartz-rich sand (SiO₂) mixed with iron-oxide-coated grains
sedimentary
Moss-covered Rock Fragment
Weathered Rock Fragment with Epilithic Growth
sedimentary
Limestone with Lichen
Calcium Carbonate (CaCO3) with Endolithic/Epilithic Lichen
sedimentary
Fossiliferous Limestone
Fossiliferous Limestone (CaCO3)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert / Flint Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Weathered gray-green rock fragment
Likely shale or mudstone; exact identification requires testing
sedimentary
Agatized Chert / Chalcedony
Silicon Dioxide (SiO2)
sedimentary
Veined Limestone
Sedimentary Calcite-Veined Rock (CaCO3)
sedimentary
Fossilized Bone Fragment
Vertebrate Fossil Material (Apatite/Calcium Phosphate)
fossil
Vesicular basalt (scoria-like basalt fragment)
Basalt; primarily plagioclase, pyroxene, and commonly olivine, with small vesicles
igneous
Jasper with Quartz Vein
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Iron-stained fossiliferous rock, possibly fossil wood
Likely silicified/petrified wood in iron-rich silica matrix; exact identification requires microscopy
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Coal (Bituminous or Anthracite)
Carbonaceous Sedimentary Rock
sedimentary
Coral Fossil (Petrified Coral)
Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)
sedimentary