Mineral, Organic Gemstone

Cultured freshwater pearls

Pearl; primarily aragonite (CaCO₃) in nacre with an organic conchiolin matrix

Polished amber inclusion specimen

Amber (fossilized plant resin), commonly succinite; organic mineraloid

Amber (likely rough amber or copal)

Fossilized tree resin; chiefly an organic polymer with terpenoid remnants

Fossilized Shell

Invertebrate fossil (Bivalvia or Brachiopoda)

Likely anthracite coal fragments

Anthracite; predominantly carbon (C), with minor mineral ash

Fossil Shell

Brachiopod or Mollusk fossil

Grass (Organic Matter/Soil)

Poaceae (family of monocotyledonous flowering plants)

Fossilized Shark Tooth

Carcharocles or Otodus sp. (Micro-fossilized)

Petrified Wood

Silicified Wood (SiO2)

Amber

Succinite (a fossilized organic resin containing succinic acid)

Chert (and/or Chalcedony)

Microcrystalline Silica (SiO2)

Chert (variations include Flint/Novaculite)

Chert (formula: SiO2)

Chert (often called Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Moss Agate

Silicon Dioxide with inclusions (SiO2 + Mn/Fe/Chlorite)

Jasper (specifically Yellow Jasper and Red Jasper)

Silicon Dioxide (SiO2) with iron oxide inclusions

Green Moss Agate

Agate (Silicon Dioxide, SiO2) with inclusions of hornblende or chlorite

Jasper

Silicon Dioxide (SiO2) with impurities

Chert (Flint)

Chert (Microcrystalline Quartz, SiO2)

Quartz vein in host rock

Quartz (SiO₂), likely in a weathered carbonate or sedimentary matrix

Chert (Yellow Jasper)

Microcrystalline Quartz (SiO2)

Chert (Iron-stained)

Chert (SiO2)

Chert (Jasper)

Silicon dioxide (SiO2)

Chert (Yellow Jasper/Flint)

Silicon dioxide (SiO2) - Cryptocrystalline Quartz

Likely coal (possibly anthracite)

Coal, composed chiefly of carbon-rich organic matter; rank cannot be confirmed from the photograph

Fossiliferous limestone

Bioclastic carbonate rock; predominantly calcite (CaCO₃)

Fossilized bone fragment

Petrified vertebrate bone; mineralized hydroxyapatite replaced or infilled by silica/carbonates

Polished green moss agate cabochon

Moss agate: microcrystalline quartz (SiO₂) with included chlorite/actinolite or iron-manganese minerals

Amber

Succinite (fossilized tree resin)

Amber

Succinate (Succinite for Baltic varieties)

Amber

Succinite (Resin)

Amber

Succinite (approximate formula C10H16O)

Amber

Succinite (C10H16O)

Shark Tooth Fossil

Chondrichthyes (shark) tooth

Chert (varietal: Flint/Jasper)

Silicon Dioxide (SiO2)

Quartz-veined Limestone

Sedimentary limestone with quartz/calcite veinlets

Pyrite

Pyrite (FeS2)

Amber

Succinite (fossilized tree resin)

Fossil Shark Tooth

Carcharocles (Otodus) sp. or similar fossilized Chondrichthyes tooth

Chert (Flint)

Chert (SiO2)

Sand Tiger Shark Tooth

Carcharias taurus

Chert with Calcite Veins

Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3) intrusions

Unidentified Dark Mineral or Rock

Indeterminate (Likely Silicon Dioxide or Carbon-based)