Organic Gemstone (Not A Mineral)

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)

Rhodochrosite

Manganese Carbonate (MnCO3)

Brachiopod Fossil in Limestone

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

Chert (often called Flint)

Chert (Microcrystalline Quartz, SiO2)

Feldspar (Orthoclase)

Orthoclase Feldspar (KAlSi3O8)

Sunstone (Heliolite)

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

Emerald in Host Rock

Beryl (Be3Al2Si6O18) containing Chromium and/or Vanadium

Septarian Nodule (Dragon Stone)

Septarian Concretion (CaCO3 with Siderite and Calcite)

Jasper

Agate/Jasper (Microcrystalline Quartz, SiO2)

Septarian Nodule (Dragon Stone)

Septarian Geode (CaCO3 + Mg + Fe)

Chert (Nodule)

Silicon Dioxide (SiO2)

Picture Jasper

Silicon Dioxide (SiO2) with iron oxide and organic impurities

Fossilized Wood (with Coal and Limonite)

Petrified Wood (Silicified or Carbonized Flora)

Petrified Wood

Silicified Wood (SiO2)

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)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

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)

Sunstone (Oregon Sunstone)

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

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)

Chert (Yellow Jasper/Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (often called Flint in this context)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Fluorite

Calcium Fluoride (CaF2)

Prehnite

Prehnite (Ca2Al(AlSi3O10)(OH)2)

Chert (and/or Flint)

Microcrystalline Quartz (SiO2)

Chert (and Flint variant)

Chert (SiO2)

Chert (and Petrified Wood)

Silicon Dioxide (SiO2)

Travertine (Tufa)

Calcium Carbonate (CaCO3)

Agatized Chert / Chalcedony

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Graphite

Graphite (Chemical Formula: C)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Red Jasper

Red Jasper (variety of Chalcedony, SiO₂)