Organic Gemstone (Not A Mineral)

Petrified Wood

Silicified Wood (SiO2)

Fossilized Brain Coral

Diploria labyrinthiformis (Fossilized)

Chert (often called Flint)

Chert (Microcrystalline Silicon Dioxide, SiO2)

Garden Quartz

Included Quartz (SiO2 with accessory minerals such as Chlorite, Hematite, or Feldspar)

Olivine (Peridot)

Magnesium Iron Silicate (Mg,Fe)2SiO4

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (often called Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Yellow Sapphire or Citrine

Al2O3 (Corundum) or SiO2 (Quartz)

Moonstone

Potassium Aluminum Silicate (KAlSi3O8)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Fairburn Agate

Cryptocrystalline Quartz (SiO2)

Rhodochrosite

Manganese carbonate (MnCO3)

Picture Jasper

Silicon Dioxide (SiO2) - Opaque Chert/Quartzite variety

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Orthoceras Fossil in Limestone

Orthoceras (extinct genus of cephalopods) in Carboniferous or Devonian Limestone

Petrified Wood

Silicified wood (Quartz/Chalcedony/Opal)

Chert (Jasper/Limonitic Chert)

Microcrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Sulfidic Mudstone with Pyrite/Goethite

Sulfidic Siltstone/Mudstone (FeS2)

Fossilized Crinoid Stem Segment

Crinoid (Phylum Echinodermata, Class Crinoidea)

Dinosaur Skull Fossil (Velociraptor Replica)

Velociraptor mongoliensis fossil specimen in sedimentary matrix

Ferruginous Chert

Microcrystalline Quartz (SiO2) with Iron Oxides

Petrified Wood

Silicified wood (primarily SiO2)

Petrified Wood (Agatized/Silicified Wood)

Silicified Paleoxylon (primarily SiO2)

Carnelian and White Quartz Bracelet

Silicon Dioxide (SiO2) - specifically Carnelian (Chalcedony) and Rock Crystal/Snow Quartz

Fossil Coral (Rugosa or Solitary Coral)

Rugosa (Order), often referred to as 'Horn Coral' (Lithostrotionella or Grewingkia)

Chert (Holey Stone)

Microcrystalline Quartz (SiO2)

Chert (and Chalcedony)

Microcrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Limestone (Concretionary or Tufa)

Calcium Carbonate (CaCO3)

Petrified Wood

Silicified Wood (primarily SiO2)

Citrine

Quartz (SiO₂) variety

Banded Chert

Cryptocrystalline Quartz (SiO2)

Sandstone (likely Fossilized Wood or Concrete Simulacrum)

Arenite / Silicified Wood / Anthropogenic Concrete

Red Jasper

Cryptocrystalline Quartz (SiO2 with Iron oxide inclusions)

Septarian Nodule or Mud Crack Fossil

Septarian Nodule (Concretion)

Petrified Wood

Silicified Wood (SiO2)

Sandstone Concretion

Sedimentary Clastic Rock (Silicate-rich)

Petrified Wood

Silicified Wood (SiO2)

Pyrite Geode (Sparkling Druzy)

Iron Sulfide (FeS2) in Sedimentary Nodule