Mineral And Organic Gemstone

Rhodochrosite

Manganese Carbonate (MnCO3)

Chert (specifically Flint or Common Chert)

Chert (Cryptocrystalline Silica, SiO2)

Feldspar (Orthoclase)

Orthoclase Feldspar (KAlSi3O8)

Chert (often called Flint)

Chert (Microcrystalline Quartz, SiO2)

Ironstone Concretion (Limonite/Goethite)

Iron oxide concretion (contains FeO(OH)·nH2O)

Petrified Wood

Silicified Wood (primarily SiO2)

Coral Fossil (Petrified Coral)

Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)

Travertine (often colloquially called Tufa)

Chemical Sedimentary Calcium Carbonate (CaCO3)

Petrified Wood

Silicified Wood (primarily Quartz / Chalcedony: SiO2)

Petrified Wood

Silicified Wood (SiO2)

Sunstone (Heliolite)

Plagioclase Feldspar ((Ca,Na)(Al,Si)4O8)

Pyrite (on host rock)

Iron Sulfide (FeS2)

Brachiopod Fossil in Limestone

Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)

Jasper

Agate/Jasper (Microcrystalline Quartz, SiO2)

Septarian Nodule (Dragon Stone)

Septarian Concretion (CaCO3 with Siderite and Calcite)

Septarian Nodule (Dragon Stone)

Septarian Geode (CaCO3 + Mg + Fe)

Green Calcite

Calcium Carbonate (CaCO3)

Petrified Wood

Silicified Wood (SiO2)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Emerald in Host Rock

Beryl (Be3Al2Si6O18) containing Chromium and/or Vanadium

Chert (Nodule)

Silicon Dioxide (SiO2)

Fossilized Wood (with Coal and Limonite)

Petrified Wood (Silicified or Carbonized Flora)

Rhodochrosite

Manganese carbonate (MnCO3)

Clear Quartz / Rock Crystal

Silicon Dioxide (SiO2)

Gemstone Sand (Mineral Assortment)

Mixed Mineral Concentrates (Commonly including Quartz SiO2, Garnet X3Y2(SiO4)3, and Tourmaline (Na,Ca)(Li,Mg,Al)3(Al,Fe,Mn)6(BO3)3(Si6O18)(OH,F)4)

Emerald in Matrix

Emerald (Beryllium Aluminum Silicate), Be3Al2(SiO3)6

Lapis Lazuli

Lapis Lazuli (A metamorphic rock primarily composed of Lazurite: (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

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.

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Sunstone (Oregon Sunstone)

Labradorite (Feldspar variety) - (Ca, Na)(Al, Si)4O8

Chert (Yellow Jasper/Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (often called Flint in this context)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (often called Flint when in chalk or limestone)

Silicon Dioxide (SiO₂)

Emerald in Matrix

Beryl (Be3Al2Si6O18) with trace amounts of Chromium/Vanadium

Petrified Wood

Silicified Wood (SiO2)

Black Marble with Quartz Veining

Metamorphosed Limestone (Recrystallized CaCO3)

Fluorite

Calcium Fluoride (CaF2)

Amber

Amber (Fossilized Tree Resin)

Prehnite

Prehnite (Ca2Al(AlSi3O10)(OH)2)

Chert (and Petrified Wood)

Silicon Dioxide (SiO2)

Travertine (Tufa)

Calcium Carbonate (CaCO3)

Chert (and/or Flint)

Microcrystalline Quartz (SiO2)