Pearl necklace
Pearl: biogenic calcium carbonate, primarily aragonite (CaCO₃), in a conchiolin matrix
gemstone
Category
Organic Gemstone (Sedimentary Associations)
Browse organic gemstone (sedimentary associations) specimens identified by the Rock Identifier community.
Learn about Organic Gemstone (Sedimentary Associations) in the encyclopedia
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Chrysocolla (Copper Ore matrix)
Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O)
mineral
Moss Agate
Silicon Dioxide (Chalcedony variety) with green hornblende or chlorite inclusions - SiO2
gemstone
Seashell (Cone Snail Shell)
Conus sp. (Calcium Carbonate, CaCO3)
fossil
Chert / Flint
Cryptocrystalline Quartz (SiO2)
sedimentary
Pink Coral
Corallium rubrum (or related species, composed of calcium carbonate)
gemstone
Red Coral
Corallium rubrum
mineral
Amber (Butterscotch/Egg Yolk Variety)
Succinite (Approx. C10H16O)
Organic Gemstone
Chert (often called Flint when dark)
Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)
sedimentary
Pearl
Nacre (primarily aragonite, CaCO₃, in an organic conchiolin matrix)
gemstone
Likely anthracite coal fragments
Anthracite; predominantly carbon (C), with minor mineral ash
sedimentary
Pearl
Organic Mineraloid (CaCO3 + Conchiolin)
mineral
Red Coral (Sponge Coral / Apple Coral)
Corallium rubrum (calcium carbonate / organic gem)
gemstone
Natural Freshwater Pearl
Calcium Carbonate (Aragonite and Calcite), CaCO3
gemstone
Black Limestone with Calcite Veining
Bituminous Limestone (CaCO3 with Organic Carbon inclusions)
sedimentary
Amber
Succinite (C10H16O)
mineraloid
Fossil Coral / Crinoid Stem section
Anthozoa / Crinoidea fossil
fossil
Amber
Succinite
mineral
Brown Jasper
Jasper (a cryptocrystalline variety of Quartz, SiO2)
Mineral, specifically a variety of Quartz
Pyrite
Pyrite (Iron sulfide, FeS₂)
Mineral
Pearl
Nacre (aragonite, CaCO₃, with conchiolin)
gemstone
Pearl
Nacre (aragonite, CaCO₃, in a conchiolin matrix)
gemstone
Green Aventurine
Aventurine (Silicon dioxide, SiO₂)
Mineral; variety of Quartz
Serpentinite
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4
metamorphic
Epidote or Unakite Rock
Epidote-bearing rock / Ca2(Al,Fe)3(SiO4)3(OH)
metamorphic
Chert / Flint
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Red Coral
Corallium rubrum
gemstone
Chert / Flint
Cryptocrystalline Quartz (Silicon Dioxide, SiO2)
sedimentary
Amber
Succinite (C10H16O)
Mineraloid (Organic)
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Nephrite Jade
Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)
metamorphic
Gold Flakes
Native Gold (Au)
mineral
Wollastonite
Calcium Inosilicate Mineral, CaSiO3
mineral
Chert (and Chalcedony)
Microcrystalline Quartz (SiO2)
sedimentary
Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite
mineral
Amber (possibly rough amber)
Fossilized tree resin; chemically a complex organic mixture, commonly classified as succinite when Baltic in origin
gemstone
Amber
Succiniferous fossil resin (C10H16O)
gemstone
Amber
Fossilized Tree Resin
gemstone
Pearl
Nacre (Aragonite and Conchiolin), CaCO3
mineral
Shale with Iron Staining
Fissile Mudrock (Sedimentary Rock)
sedimentary
Red Coral (Precious Coral)
Corallium rubrum (Calcium Carbonate, CaCO3)
gemstone
Amber
Succinited (C10H16O)
fossil