Organic Gemstone (Succinite)

Pink Opal

Amorphous Hydrous Silica (SiO2·nH2O)

Likely weathered flint or chert fragment

Cryptocrystalline quartz (SiO₂), possibly siliceous chert/flint

Jasper

Silicon Dioxide (SiO2) with impurities

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Chalcopyrite

CuFeS2

Blue Apatite

Apatite - Ca5(PO4)3(F,Cl,OH)

Chert (Flint)

Microcrystalline Opaline Silica (SiO2)

Moss Agate

Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide

Amber

Fossilized Tree Resin (Succinate)

Angel Skin Coral

Corallium rubrum / Corallium spp. (Calcium Carbonate, CaCO3)

Chert (variant Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline quartz (SiO2)

Chert (specifically Flint or Novaculite variant)

Chert (Microcrystalline Quartz, SiO2)

Moss Agate

Silicon Dioxide (Chalcedony with green mineral inclusions), SiO2

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Dyed Agate (Tumbled)

Silicon Dioxide (Chalcedony variety, artificially dyed)

Chert (Black Chert or Flint)

Silicon Dioxide (SiO2)

Chert (varieties include Flint and Jasper)

Silicon Dioxide (SiO2) / Microcrystalline Quartz

Banded Agate (Dyed)

SiO2 (Silicon Dioxide / Microcrystalline Quartz)

Petrified Wood

Silicified Wood (SiO2)

Tumbled brown jasper (likely common jasper or chert)

Microcrystalline quartz, SiO₂, chiefly chalcedony/quartz with iron-oxide impurities

Chert (specifically Flint or Jasper variant)

Microcrystalline silica (SiO2)

Chert Nodule

Microcrystalline Silica (SiO2)

Chert (Flint)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Red Chert (Jasper)

Cryptocrystalline Quartz (SiO2) with iron oxide inclusions

Jasper

Jasper (Cryptocrystalline variety of Quartz, SiO2)

Fossil Coral

Phylum Cnidaria / Rugosa or Tabulata

Chert (Flint)

Chert (Microcrystalline Silica, SiO2)

Chert (specifically Flint or Jasper variant)

Microcrystalline Quartz (SiO2)

Chert (Flint/Jasper)

Microcrystalline Quartz (SiO2)

Polished banded agate (likely picture jasper or petrified wood)

Microcrystalline quartz, SiO₂, with iron-oxide and clay inclusions

Petrified Wood

Silicified Wood (primarily SiO2)

Petrified Wood

Silicified Paleoxylon (SiO2)

Moss Agate

Silicon Dioxide (SiO2) with Manganese/Iron Oxide inclusions

Jasper

Silicon Dioxide (SiO2) with iron oxide impurities

Turquoise, Pearl, and Coral Necklace

CuAl6(PO4)4(OH)8·4H2O (Turquoise) / CaCO3 (Pearl and Coral)

Red Jasper

Quartz (SiO2) with iron oxide inclusions

Chert (variations include Flint)

Sedimentary cryptocrystalline quartz (SiO2)

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Chert (Nodule)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)