Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Organic Gemstone (Sedimentary classification)
Category
Organic Gemstone (Sedimentary Classification)
Browse organic gemstone (sedimentary classification) specimens identified by the Rock Identifier community.
Learn about Organic Gemstone (Sedimentary Classification) in the encyclopedia
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Pearls
Pearl: biomineralized aragonite (CaCO₃) and conchiolin
gemstone
Bituminous Coal (with Anthracite or Vitrinite inclusion)
Organic-rich Sedimentary Rock (Carboniferous classification)
sedimentary
Mixed Rock and Mineral Collection
Various geological specimens
igneous, sedimentary, and metamorphic
Polished kambaba jasper
Orbicular stromatolitic jasper; microcrystalline quartz (SiO₂) with chlorite/amphibole-rich inclusions
sedimentary
Conglomeratic breccia
Clast-supported polymictic conglomerate/breccia, cemented by silica- or carbonate-rich matrix
sedimentary
Polished red gemstone pendant, likely red jasper or brecciated jasper
Jasper: microcrystalline quartz (SiO₂), commonly with hematite or iron-oxide inclusions
metamorphic
Red Siltstone
Siltstone (composed mainly of SiO2 and Fe2O3)
sedimentary
Ammonite Fossil
Ammonoidea
fossil
Iron Meteorite
Siderite (Iron-Nickel alloy)
meteorite
Iron Meteorite
Siderite (Iron-Nickel Alloy)
meteorite
Iron Meteorite
Siderite (Iron-Nickel Alloy)
meteorite
Lunar Breccia Meteorite
Lunar Feldspathic Breccia
igneous
Moss Agate
Silicon Dioxide with inclusions (SiO2 + impurities)
mineral
Blue opalite (often sold as synthetic opal)
Opalite glass; amorphous hydrated silica if natural opal (SiO₂·nH₂O)
gemstone
Zebra Jasper
Tektite variety of Silicon Dioxide (SiO2) with inclusions
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Chondrite Meteorite
L or H Ordinary Chondrite
meteorite
Lunar Meteorite (Feldspathic Breccia)
Lunar Feldspathic Breccia
igneous
Greenschist
Greenschist (containing Chlorite, Epidote, and Actinolite)
metamorphic
Sandstone
Arenite (Secondary classification based on grain size)
sedimentary
Rounded gray-brown cobble, likely weathered sandstone or quartzite
Tentatively quartz-rich sandstone (SiO₂-dominated); exact identification requires hardness and acid tests
sedimentary
Tumbled Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide
mineral
Dark metamorphic rock, likely hornfels or fine-grained basalt
Probable hornfels; commonly quartz–feldspar–mica with variable amphibole/pyroxene
metamorphic
Quartz-rich chalcedony (likely silicified rock)
Microcrystalline quartz, SiO₂; possibly silicified limestone or jasper
mineral
Granite (likely biotite granite)
Coarse-grained granitic rock; chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende
igneous
Script Jasper
Silicon Dioxide (SiO2) with impurities
sedimentary
Amber
Succinates (Organic Gemstone)
mineral
Lunar Highlands Breccia (Meteorite)
Lunar Feldspathic Breccia
igneous
Martian Meteorite (Black Beauty)
Martian (basaltic breccia) Meteorite, Northwest Africa (NWA) 7034
igneous
Quartz-rich rock fragment, possibly chert or weathered quartz
Microcrystalline quartz (SiO₂), tentative identification
mineral
Amber
Succinrite (Organic Gemstone)
mineraloid
Lunar Feldspathic Breccia
Lunar Meteorite (Feldspathic Regolith Breccia)
igneous
Red jasper pebble
Microcrystalline quartz (chalcedony), SiO₂, colored by iron oxides
metamorphic
Sandstone Cobble
Arenite (Secondary classification based on grain size)
sedimentary
Mixed tumbled stones
Mixed mineral specimens; visible pieces may include quartz, feldspar, calcite, and other silicates
mineral
Dalmatian jasper (likely orbicular microgranite)
Quartz–feldspar–biotite/pyroxene microgranite; commonly marketed as Dalmatian jasper
igneous
Granite countertop slab
Granite; primarily quartz, feldspar, and mica (commonly biotite), with accessory amphibole/iron oxides
igneous
Amber
Succinicum (C10H16O)
mineral
Rounded river cobble, likely weathered sandstone or quartz-rich metasandstone
Indeterminate sandstone; commonly quartz (SiO₂) with feldspar, lithic grains, and iron-oxide cement
sedimentary
Amber (Copal)
Fossilized Tree Resin
mineraloid
Chondrite Meteorite
L or H Ordinary Chondrite
meteorite