Chert (Commonly known as Flint)
Microcrystalline Quartz (SiO2)
Category
Browse organic gemstone (biogenic) specimens identified by the Rock Identifier community.
Chert (Commonly known as Flint)
Microcrystalline Quartz (SiO2)
Chert / Flint
Cryptocrystalline Quartz (Silicon Dioxide, SiO2)
Chert (Flint variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Chert / Flint
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Red Jasper
Jasper (Silicon Dioxide, SiO2 with iron oxide impurities)
Chert (often called Flint or Jasper)
Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)
Chert (varieties include Flint and Jasper)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert / Flint
Cryptocrystalline Quartz (SiO2)
Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
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 ).
Chert (Jasper variety)
Silicon Dioxide (SiO2)
Chert (specifically Flint or Jasper variant)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (and Chalcedony)
Microcrystalline Quartz (SiO2)
Chert (Cherty Flint/Jasper variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Pyrite
Pyrite (Iron sulfide, FeS₂)
Pearl
Calcium Carbonate (Aragonite or Calcite) and Conchiolin
Chert (Jasper variation)
Chert (SiO2)
Banded Chert
Cryptocrystalline Quartz (SiO2)
Mother of Pearl (Nacre)
Calcium Carbonate (primarily aragonite, with conchiolin)
Amber (Simulated/Faturan Style)
Resin mix (Likely Phenolic/Celluloid if synthetic, Succinite if natural)
Baltic Amber (Butterscotch variety)
Succinite
Baltic Amber (Butterscotch or Egg Yolk Variety)
Succinite (C10H16O)
Baltic Amber (Butterscotch or Egg Yolk Variety)
Fossilized Tree Resin (Succinite); Approximate formula: C10H16O
Pyrite
Pyrite (FeS2)
Pearls
Aragonite (calcium carbonate) and Conchiolin
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.
Hand-Drawn Trading Card (Amateur Artwork)
Cellulose-based substrate with wax/graphite/ink deposit (n/a for minerals)
Amber
Fossilized Tree Resin (Amorphous Hydrocarbon)
Opalite (a synthetic glass, often confused with Opal)
Silicon dioxide glass (SiO2nH2O, for natural opal)
Pyrite
Pyrite (Iron Disulfide), FeS2
Chert / Flint
Chert (varieties include Flint)
Baltic Amber (Butterscotch or Egg Yolk Variety)
Succinite (C10H16O)
Red Coral
Corallium rubrum (for precious red coral), although other species like Corallium japonicum and Paracorallium are also used.
Calcite in Matrix
Calcium Carbonate (CaCO3)
Oyster Shell (Biogenic Calcium Carbonate)
Crassostrea virginica (or related species) - Calcium Carbonate (CaCO3)
Calcite (likely a tumbled specimen)
Calcite (CaCO 3 )
Calcite
Calcite (Mineral; CaCO₃)
Calcite
Calcite (Calcium Carbonate, CaCO3)
Calcite
Calcite (CaCO3)
Chert (or possibly Flint)
SiO2 (Silicon Dioxide)
Calcite
Calcite (CaCO3)