Chert (Chalk-associated Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Category
Organic Gemstone (Often Associated With Sedimentary Sequences)
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
Learn about Organic Gemstone (Often Associated With Sedimentary Sequences) in the encyclopedia
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Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Chert (Black Chert / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert Pebble (Flint)
Microcrystalline/Cryptocrystalline Quartz (SiO2)
sedimentary
Septarian Nodule (Polished)
Septarian concretion (Calcite, Aragonite, Limestone)
sedimentary
Fossilized Megalodon Tooth Fragment
Otodus megalodon (Carcharocles megalodon fossil)
sedimentary
Chert (Field Stone)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Jasper/Agate mix)
Microcrystalline Quartz (SiO2)
sedimentary
Malachite in Host Rock
Malachite - Cu2CO3(OH)2
mineral
Chert (specifically Chalcedony/Flint variant)
Silicon Dioxide (SiO2)
sedimentary
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Bumblebee Jasper
Fibrous Calcite with Arsenic and Sulfur Inclusions
gemstone
Graphite Schist
C (Carbonaceous Schist)
metamorphic
Diorite
Phaneritic intermediate intrusive igneous rock
igneous
Chert (Light Variety)
Sedimentary cryptocrystalline quartz (SiO2)
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Petrified Wood
Silicified Wood (primarily SiO2)
fossil
Agate
Silicon dioxide (Chalcedony), SiO2
gemstone
Red Jasper
Jasper (Silicon Dioxide) - SiO2
sedimentary
Unakite
Epidotized Granite
metamorphic
Red Jasper (Chert)
Silicon Dioxide (SiO2)
sedimentary
Amethyst
Amethyst (SiO₂)
Mineral
Chert (Black Flint)
Silicon Dioxide (SiO2)
sedimentary
Chert (specifically Yellow/Brown Chert or Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Ironstone Concretion
Siderite or Hematite Concretion
sedimentary
Red Coral
Corallium rubrum (for precious red coral), although other species like Corallium japonicum and Paracorallium are also used.
Organic Gemstone (not a rock or mineral in the traditional sense, but bio-mineralized material)
Fossiliferous Limestone
Sedimentary Limestone (CaCO3) containing Crinoid or Brachiopod remains
fossil
Pink Opal
Hydrated amorphous silica (SiO2·nH2O)
gemstone
Strawberry Quartz
Quartz (SiO2) with inclusions of Goethite or Hematite
Mineral
Arsenopyrite with Quartz
Arsenopyrite (FeAsS)
mineral
Chert Pebble
Microcrystalline Quartz (SiO2)
sedimentary
Yellow Chert (River Stone)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
sedimentary
Aquamarine
Beryl (Be3Al2Si6O18 with Fe2+ impurities)
mineral
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Amber
Fossilized Tree Resin (C10H16O)
gemstone
Quartz
Silicon Dioxide (SiO2)
mineral
Fuchsite (Chrome Mica)
Chromian Muscovite - K(Al,Cr)2(AlSi3O10)(OH)2
mineral
Chert (Gravel)
Microcrystalline Quartz (SiO2)
sedimentary
Pearl
Nacre (Aragonite and Conchiolin), CaCO3
mineral
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
sedimentary
Fossilized Pycnodonte Oyster
Pycnodonte (Gryphaeostrea) species; Composition is Calcium Carbonate (Calcite/Aragonite)
sedimentary