Organic Gemstone (Often Associated With Sedimentary Sequences)

Rhodochrosite

Manganese Carbonate (MnCO3)

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxides)

Turquoise with Pyrite

Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O] with Iron Pyrite (FeS2)

Chert (Yellow/Brown Jasper)

Silicon Dioxide (SiO2)

Flint or chert

Microcrystalline quartz (SiO₂), commonly called flint when dark and nodular

Jasper

Silicon Dioxide (SiO2) with impurities

Pink Coral

Corallium rubrum (Calcium Carbonate, CaCO3)

Limestone (specifically Bituminous or Carbonaceous Limestone)

Calcium Carbonate (CaCO3) with Organic Impurities

Lapis Lazuli (in jewelry setting)

Na8[Al6Si6O24]n(S,Cl,SO4,OH)2 (Lazurite-rich rock)

Rhodonite

Rhodonite (Manganese Iron Magnesium Calcium Silicate - (Mn,Fe,Mg,Ca)SiO3)

Chrysocolla

Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O)

Amber

Succinite (a fossilized organic resin)

Chert (and/or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Jade Dice

Nephrite / Jadeite (Ca2(Mg,Fe)5Si8O22(OH)2 or NaAlSi2O6)

Chert (often called Flint)

Chert (Silicon Dioxide, SiO2)

Prehnite

Prehnite (Ca2Al(AlSi3O10)(OH)2)

Moss Agate

Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxide

Amygdaloidal Basalt

Amygdaloidal Basalt

Peach Moonstone (Orange/Peach Feldspar)

Potassium aluminum silicate (KAlSi3O8)

Apache Tear (Obsidian)

Volcanic Glass (Amorphous Silicon Dioxide)

Yellow Jasper

Silicon Dioxide (SiO2) with Goethite/Iron oxide inclusions

Amber

Succinite (fossilized resin)

Chrysocolla in Matrix

Hydrated copper phyllosilicate mineral (Cu,Al)2H2Si2O5(OH)4·nH2O

Amazonite

Microcline (KAlSi3O8) with lead impurities

Prehnite

Ca2Al(AlSi3O10)(OH)2

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Cordierite (Iolite) in Quartz

Cordierite (Magnesium iron aluminium cyclosilicate) - Mg2Al4Si5O18

Amber

Succinates (Fossilized Tree Resin)

Imperial Topaz

Al2SiO4(F,OH)2

Sodalite in Feldspar Matrix

Sodalite (Na8(Al6Si6O24)Cl2)

Rhodonite

Manganese Silicate (Mn,Fe,Mg,Ca)SiO3

Agate

Silicon dioxide (Chalcedony), SiO2

Chert (Jasper/Flint variety)

Silicon Dioxide (SiO2)

Quartz with Mica/Host Rock

Silicon Dioxide (SiO2) with Phyllosilicates

Chert (Jasper/Agate Peat)

Microcrystalline Quartz (SiO2)

Sunstone

Heliolite (Aventurine Feldspar, (Ca,Na)((Al,Si)2Si2O8))

Hematite

Iron(III) oxide (Fe2O3)

Amygdaloidal Basalt with Epidote

Amygdaloidal Basalt (Ca2(Al,Fe)3(SiO4)3(OH))

Chert (Agatized/Chalcedony variety)

Microcrystalline Quartz (SiO2)

Black Sapphire (Basaltic Blue Sapphire)

Corundum (Al2O3)

Fluorite

Calcium Fluoride (CaF2)