Organic Gemstone (Sedimentary Associations)

Quartz Crystal

Quartz (SiO₂)

Lazulite

Lazulite (Mg,Fe2+)Al2(PO4)2(OH)2

Chert (White-Tan variety)

Silicon dioxide (SiO2) / Microcrystalline Quartz

Milky Quartz

Silicon Dioxide (SiO2)

Serpentinite

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4

Erythrite

Erythrite (Cobalt Bloom) - Co3(AsO4)2·8H2O

Limonite (vibrant yellowish-brown iron oxide)

Limonite (FeO(OH)·nH2O)

Lapis Lazuli

Lazurite-dominant Metamorphic Rock (complex aluminosilicate)

Chert (Commonly known as Flint or Jasper when pigmented)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper variety)

Chert (SiO2)

Amber

Succinates (Organic compound: C10H16O)

Arfvedsonite with Garnet

Na3(Fe2+,Mg)4Fe3+Si8O22(OH)2

Chert (Flint)

Microcrystalline or cryptocrystalline quartz (SiO2)

Yellow Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Amber

Succinite (C10H16O)

Shattuckite (Blue Quartz/Jasper Matrix)

Shattuckite (Copper Silicate Hydroxide - Cu5(SiO3)4(OH)2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Pyrite

Iron Disulfide (FeS2)

Pyrite in Shale

Iron Disulfide (FeS2)

Black Freshwater Pearls

Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert (specifically Flint or Jasper variant)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Red Coral

Corallium rubrum

Chert (often called Flint when dark)

Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)

Amber

Succinite (fossilized resin, C10H16O)

Quartz on Chlorite Schist

Chlorite Schist (Mg,Fe)3(Si,Al)4O10(OH)2 with Quartz (SiO2)

Chert (Cherty Flint/Jasper variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Ferruginous Quartz

Silicon Dioxide (SiO2) with Limonite/Hematite inclusions

Tektite (likely Australite)

Tektite (no specific chemical formula as it's a natural glass of variable composition, mostly SiO2, Al2O3, FeO, MgO, CaO, K2O, Na2O, TiO2)

Chert (often called Flint or Jasper)

Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)

Chert / Flint

Cryptocrystalline Quartz (Silicon Dioxide, SiO2)

Black Limestone with Calcite Veining

Bituminous Limestone (CaCO3 with Organic Carbon inclusions)

Pearl

Calcium Carbonate (Aragonite) with Conchiolin; formula: CaCO3

Amber

Succinite

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Amethyst and Citrine (Quartz variants)

Silicon Dioxide (SiO2)

Amber

Succinite (fossilized resin)

Chert / Flint

Cryptocrystalline Quartz (SiO2)

Chert (varieties include Flint and Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Rose Quartz

Silicon dioxide (SiO2)

Moss Agate

Chalcedony (SiO2) with inclusions of manganese or iron oxide