Chert (Cherty Flint/Jasper variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Category
Mineraloid (Organic Gemstone)
Browse mineraloid (organic gemstone) specimens identified by the Rock Identifier community.
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Pyrite
Pyrite (Iron sulfide, FeS₂)
Mineral
Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Organic Gemstone (Sedimentary classification)
Amber-like beach pebble
Amber (fossilized tree resin), likely heavily weathered or resinous organic material; exact identification is uncertain from the image
gemstone
Likely anthracite coal fragments
Anthracite; predominantly carbon (C), with minor mineral ash
sedimentary
Chert (Jasper variation)
Chert (SiO2)
sedimentary
Coral (Precious Coral)
Corallium rubrum (Red Coral), Paracorallium japonicum (Momo Coral), Pleurocorallium elatius (Sardinian Coral), various other species within the Corallidae family. Chemically, it's primarily Calcium Carbonate (CaCO 3 ).
Mineral, Organic Gemstone
Banded Chert
Cryptocrystalline Quartz (SiO2)
sedimentary
Mother of Pearl (Nacre)
Calcium Carbonate (primarily aragonite, with conchiolin)
Organic Gemstone/Biomineral
Amber (Simulated/Faturan Style)
Resin mix (Likely Phenolic/Celluloid if synthetic, Succinite if natural)
Organic Gemstone (not a mineral)
Pyrite
Pyrite (FeS2)
Mineral
Baltic Amber (Butterscotch or Egg Yolk Variety)
Fossilized Tree Resin (Succinite); Approximate formula: C10H16O
Organic Gemstone (Succinite)
Hand-Drawn Trading Card (Amateur Artwork)
Cellulose-based substrate with wax/graphite/ink deposit (n/a for minerals)
Organic/Synthetic Composite (Paper and Pigment)
Opalite (a synthetic glass, often confused with Opal)
Silicon dioxide glass (SiO2nH2O, for natural opal)
Synthetic (glass)
Amber
Fossilized Tree Resin (Amorphous Hydrocarbon)
Mineral
Baroque Pearl (and potentially a small Sapphire/Blue Topaz)
Pearl: Calcium Carbonate (aragonite or calcite) with conchiolin. Sapphire: Aluminum Oxide (Al2O3). Blue Topaz: Al2SiO4(F,OH)2.
Organic Gemstone (for pearl), Mineral (for sapphire/topaz)
Chert / Flint
Chert (varieties include Flint)
Sedimentary
Pyrite
Pyrite (Iron Disulfide), FeS2
Mineral
Baltic Amber (Butterscotch or Egg Yolk Variety)
Succinite (C10H16O)
Organic Gemstone (fossilized resin)
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)
Manganese Dendrite on Siltstone
Manganese Oxide (pyrolusite or psilomelane) Dendrites
mineral/sedimentary
Citrine
Silicon Dioxide (SiO2)
mineral
Labradorite
(Ca, Na)(Al, Si)4O8 (Calcium Sodium Aluminum Silicate)
mineral
Cat's Eye Moonstone (Feldspar)
Orthoclase (KAlSi3O8) with Albite (NaAlSi3O8) inclusions
mineral
Pearl
Calcium Carbonate (Aragonite) - CaCO3
mineral
Charoite
Charoite (K(Ca,Na)2Si4O10(OH,F)·nH2O)
metamorphic
Hypersthene
Enstatite (Hypersthene variety), (Mg,Fe)SiO3
mineral
Dendritic Agate (or Dendritic Opal)
SiO2 (for Agate), SiO2·nH2O (for Opal)
Mineral
Potassium feldspar
Orthoclase or microcline; KAlSi₃O₈
mineral
Blue glass-like tumbled specimen
Most likely cobalt-blue slag glass or manufactured glass; not confidently identifiable as a natural mineral from the image
mineral
Pearl (Biogenic Gemstone)
Calcium Carbonate (Aragonite and Calcite) with Conchiolin
gemstone
Pearl
Aragonite (CaCO3) with Conchiolin
mineral
Pearl
Calcium Carbonate (primarily Aragonite and Calcite), CaCO3
mineral
Hypersthene
(Mg,Fe)SiO3 - Enstatite-Ferrosilite series
mineral
Weathered iron-rich rock, possibly limonite-bearing sandstone or laterite
Limonite/goethite mixture (hydrated iron oxides), composition uncertain from image
sedimentary
Pearl (as a biogenic mineral/gemstone)
Calcium Carbonate (mostly Aragonite), CaCO3
mineral
Prasiolite and Quartz Crystal Cluster
Quartz (SiO2); Prasiolite is a variety of Quartz
mineral
Cubic Zirconia
Zirconium dioxide (ZrO2)
mineralogical simulant / gemstone