Limonite
Limonite (Hydrated iron(III) oxide-hydroxide) FeO(OH)·nH2O
mineral
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
View all →
Black Pearl (Tahitian Pearl)
Aragonite / Calcite (CaCO3) with Conchiolin
mineral
Petrified Wood
Silicified Wood (primarily Chalcedony/Quartz, SiO2)
fossil
Limestone (specifically Bituminous or Carbonaceous Limestone)
Calcium Carbonate (CaCO3) with Organic Impurities
sedimentary
Chert (Nodular or Massive Variety)
Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Milky quartz
Quartz (silicon dioxide, SiO₂)
mineral
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Precious Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
gemstone
Chert (Gray Chalcedony)
Microcrystalline Quartz (SiO2)
sedimentary
Chrysocolla (or Turquoise/Aventurine)
Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O
mineral
Chert (Agatized/Chalcedony variety)
Microcrystalline Quartz (SiO2)
sedimentary
Emerald
Beryl (Be3Al2Si6O18) with trace amounts of Chromium and/or Vanadium
mineral
Chert (Jasper/Flint variant)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Chert (Chalcedony/Agate)
Microcrystalline Quartz (SiO2)
sedimentary
Pyrite
Iron Disulfide (FeS2)
mineral
Carnelian (Orange Chalcedony)
Silicon Dioxide (SiO2)
mineral
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Chert (specifically Jasper or Flint type)
Microcrystalline Quartz (SiO2)
sedimentary
Amber
Succinate (Fossilized Tree Resin)
gemstone
Amber / Fossilized Resin
Succinite / Fossilized Tree Resin
mineral
Chert (Field Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Limonite with Gossan / Iron Ore
Hydrated iron oxide-hydroxide, approximately FeO(OH)·nH2O
mineral
Chert (variations include Flint or Jasper)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Amethyst, Aquamarine, and Pearl Ring
SiO2 (Amethyst), Be3Al2Si6O18 (Aquamarine), CaCO3 (Pearl)
gemstone
Chert (Nodule)
Microcrystalline Quartz (SiO2)
sedimentary
Turquoise (likely stabilized or Howlite/Magnesite imitation)
Hydrated phosphate of copper and aluminium, CuAl6(PO4)4(OH)8·4H2O
mineral
Green Fluorite
Fluorite (Calcium Fluoride, CaF2)
mineral
Prehnite
Prehnite, Ca2Al(AlSi3O10)(OH)2
mineral
Honey calcite (yellow calcite)
Calcite, calcium carbonate (CaCO₃)
mineral
Chert (Green variety)
Microcrystalline Opaline/Quartz (SiO2)
sedimentary
Quartz (on matrix)
Quartz (Silicon Dioxide, SiO₂)
Mineral
Chert (Quartz Variety)
Microcrystalline Silica (SiO2)
sedimentary
Chert / Flint
Silicon Dioxide (SiO₂)
sedimentary
Chert (variations include Flint or Jasper)
Silicon Dioxide (SiO2)
sedimentary
Amber
Succinite (C10H16O)
mineral
Pearl necklace
Pearl (biogenic calcium carbonate, chiefly aragonite; CaCO₃)
gemstone
Honey calcite
Calcite (CaCO₃), likely iron-stained honey/orange variety
mineral
Red Coral (with Hematite and Black Pearl accents)
Corallium rubrum (Calcium Carbonate, CaCO3)
mineral
Probable amber fragment
Amber (fossilized plant resin; chiefly amorphous organic resin, commonly dominated by succinite)
gemstone
Chert (specifically Red Chert/Jasper variety)
Silicon Dioxide (SiO2)
sedimentary
Amber
Succinite (Approximate formula: C10H16O)
mineral