Dendritic Agate
Chalcedony (SiO2) with manganese/iron oxide inclusions
mineral
Category
Mineral And Organic Gemstone
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Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxides
mineral
Chert (Jasper variety)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Chert (Yellow Jasper/Flint)
Silicon dioxide (SiO2) - Cryptocrystalline Quartz
sedimentary
Carnelian
Carnelian (SiO2)
mineral
Carnelian
Carnelian (Silicon Dioxide: SiO2)
mineral
Serpentinite
Serpentinite (composed primarily of Serpentine group minerals, e.g., Antigorite, Lizardite, Chrysotile)
metamorphic
Green Calcite
Calcium Carbonate (CaCO3)
mineral
Tiger's Eye (often misinterpreted as Gold Ore in this context)
Pseudomorph of Quartz after Crocidolite (SiO2)
metamorphic
Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
sedimentary
Moss Agate
Silicon Dioxide (SiO2) with Chlorite/Hornblende inclusions
mineral
Tree Agate
Dendritic Agate (Silicon Dioxide, SiO2)
mineral
Rough Garnet (Almandine)
Almandine Garnet (Fe3Al2(SiO4)3)
mineral
Jasper
Silicon dioxide (SiO2) with impurities
sedimentary
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Sandstone with Iron Oxide Concretion
Arenite with Hematite/Goethite Concretion
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Chert (specifically Flint or Common Chert)
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2 - Quartz/Chalcendony replacing organic matter)
sedimentary
Banded Chert
Silicon Dioxide (SiO2)
sedimentary
Fairy Stone (Menilite Concretion)
Carbonate-rich concretion (often Siderite or Calcite in Clay)
sedimentary
Chert (Iron-stained)
Silicon Dioxide (SiO2)
sedimentary
Glauconitic Sandstone
Glauconitic Quartz Sandstone (K(Fe,Al)2(Si,Al)4O10(OH)2)
sedimentary
Chert
Silicon dioxide (SiO2)
Sedimentary
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Nodular or Massive Variety)
Cryptocrystalline Quartz (SiO2)
sedimentary
Diamond
Diamond (pure Carbon, C)
mineral
Rough Diamond
Carbon (C)
mineral
Chert / Flint
Silicon Dioxide (SiO₂)
sedimentary
Ironstone Concretion
Siderite or Limonite Concretion (FeCO3 or FeO(OH)·nH2O)
sedimentary
Chert (includes Flint & Jasper)
Chert (Siliceous sedimentary rock, chemical formula SiO2)
sedimentary
Siltstone
Siltstone
sedimentary
Bloodstone (Heliotrope)
SiO2 (Silicon Dioxide with Iron Oxide inclusions)
sedimentary
Sodalite Syenite (popularly known as Yooperlite)
Sodalite-rich Syenite (composed of alkali feldspar and sodalite)
Igneous
Chert (Jasper/Flint variant)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (varieties include Flint and Jasper)
Silicon Dioxide (SiO2)
sedimentary
Diamond (Cluster Ring)
Carbon (C)
mineral
Rough Diamond
Diamond (Native Carbon), C
mineral
Pink Granite
Phaneritic Plutonic Felsic Rock (Granite)
igneous
Diamond
Natural Carbon (C)
mineral
Blue Sapphire
Corundum (Al2O3) with traces of Iron and Titanium
mineral