Chert (Yellow Jasper variant)
Microcrystalline Quartz (SiO2)
sedimentary
Category
Organic Gemstone (Not A Rock Or Mineral)
Browse organic gemstone (not a rock or mineral) specimens identified by the Rock Identifier community.
Learn about Organic Gemstone (Not A Rock Or Mineral) in the encyclopedia
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Red Jasper with Quartz
Microcrystalline Quartz (SiO2)
sedimentary
Banded Chert
Microcrystalline Quartz (SiO2)
sedimentary
Ironstone Concretion
Ironstone (Siderite/Goethite/Hematite matrix)
sedimentary
Sandstone with Iron Staining
Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)
sedimentary
Amber (Tumbled/Polished)
Succinite (Fossilized Tree Resin)
mineraloid
Pearl
Calcium carbonate (CaCO3) + organic conchiolin (Biogenic Mineral)
mineral
Travertine (Tufa)
Chemical Sedimentary Rock (CaCO3)
sedimentary
Moonstone
Orthoclase (Potassium Aluminum Silicate), Formula: (K,Na)AlSi3O8
mineral
Shale with Coprolite influence
Argillaceous sedimentary rock (Shale/Mudstone)
sedimentary
Moss Agate (Crescent Moon Shape)
Silicon Dioxide (SiO2) with iron/manganese inclusions
mineral
Polished agate (likely plume or moss agate)
Chalcedony, microcrystalline quartz (SiO₂), with iron-oxide and possible chlorite inclusions
mineral
Shale (possibly Carbonaceous or Oil Shale)
Argillaceous Sedimentary Rock
sedimentary
Yellow amber beads
Amber (fossilized tree resin; organic mineraloid, not a true mineral)
gemstone
Amber (polished piece)
Fossilized tree resin; amber is an organic mineraloid, not a true mineral
gemstone
Amber
Fossilized plant resin; primarily organic terpenoid compounds (not a mineral)
gemstone
Amber (Rough)
Succinite (Resinite)
gemstone
Tumbled moss agate (likely)
Chalcedony, microcrystalline quartz (SiO₂), with iron/manganese inclusions
gemstone
Quartz (Orange/Pink variety)
Silicon Dioxide (SiO2)
mineral
Purple Chalcedony
Silicon Dioxide (SiO2)
mineral
Shungite
Shungite (carbon-rich Precambrian rock)
mineral
Chert / Chalcedony
Silicon Dioxide (SiO2)
sedimentary
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Pearl (Biogenic Mineral)
Calcium Carbonate (primarily Aragonite) with Conchiolin; CaCO3
mineral
Coal (most likely Bituminous or Anthracite)
Coal (organic sedimentary rock)
Sedimentary
Petrified Wood
Silicified wood (Quartz/Chalcedony - SiO2)
mineral
Agatized Petrified Wood
Silicon Dioxide (SiO2) - Chalcedony pseudomorph after Wood
metamorphic
Granite / Feldspar gravel
Granite (felsic intrusive igneous rock)
igneous
Fossil bivalve shell
Ribbed pectinid or related bivalve; originally calcite/aragonite (CaCO₃), likely partially mineralized
fossil
Spessartine Garnet in Quartz/Feldspar Pegmatite
Spessartine (Mn3Al2(SiO4)3) in Quartz (SiO2) and Feldspar
Mineral in Igneous Rock
Pyrite in Slate or Shale
Iron Sulfide (FeS2) in Argillaceous Matrix
mineral
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Concrete or asphalt-like aggregate surface with a dark fragment
Uncertain; likely artificial concrete containing mixed lithic aggregate, not a natural rock
sedimentary
Jasper
Silicon dioxide (SiO2)
sedimentary
Glauconite (Greensand)
(K, Na)(Fe3⁰, Al, Mg)₂(Si, Al)₄O₁₀(OH)₂
sedimentary
Shungite
Fullerene-bearing carbonaceous rock
mineral
Fossil Shark Tooth
Selachii (fossilized dentition)
fossil
Pyrite in Shale
Iron Sulfide (FeS2) in Sedimentary Matrix
mineral
Sandstone (Glauconitic)
Glauconitic Quartz Sandstone (SiO2 + (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Chert (Flint)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
River Rock
Silica-rich water-worn rock
sedimentary