Gneiss (Banded Gneiss)
Gneiss
Category
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Gneiss (Banded Gneiss)
Gneiss
Chert (Flint variety)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified wood (principally SiO2)
Petrified Wood
Silicified Wood (SiO2)
Druzy Quartz
Silicon Dioxide (SiO2)
Precious Opal
Hydrated Silica (SiO2·nH2O)
Carnelian (Chalcedony)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Basalt
Basalt (Mafic volcanic rock)
Quartz Pebble
Silicon Dioxide (SiO2)
Chert (often found as Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Citrine Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Fossilized Coral (Petoskey-like or Favosites)
Anthozoa (Fossilized Coral)
Shungite
Shungite (carbon-rich Precambrian mineraloid)
Amethyst
Silicon dioxide (variant with ferric iron impurities), SiO2
Carnelian Agate
Silicon Dioxide (SiO2) with iron oxide inclusions
Gold Nugget
Native Gold (Au)
Mica Schist
Mica Schist
Blue-dyed Quartz Druzy
Silicon Dioxide (SiO2) with artificial pigment
Iron-stained Quartz
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
Petrified Wood
Silicified Wood (SiO2)
Ferruginous Quartz
Silicon Dioxide with Hematite/Limonite inclusions (SiO2 + Fe2O3)
Quartz
Silicon Dioxide (SiO2)
Quartz Geode (Water-worn)
Silicon Dioxide (SiO2)
Smoky Quartz
Smoky Quartz (Silicon Dioxide, SiO2)
Quartz (Smoky/Milky variant)
Silicon Dioxide (SiO2)
Rose Quartz
SiO2 (Silicon Dioxide)
Agatized Fossil (Druzy Agate)
Silicon Dioxide (SiO2) replacing organic matter
Hematite (beads)
Hematite (Fe₂O₃)
Quartz (Common or Milky)
Silicon Dioxide (SiO2)
Rough Sapphire
Corundum (Al2O3)
Petrified Wood
Silicified Wood (primarily Chalcedony/Quartz, SiO2)
Black Tourmaline
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
Obsidian
Amorphous volcanic glass (primarily SiO2)
Milky Quartz with Iron Inclusions
Crystalline Silicon Dioxide (SiO2)
Milky Quartz with Iron Staining
Silicon Dioxide (SiO2)
Moss Agate
Silicon Dioxide (SiO2) with Manganese or Iron Oxide inclusions
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, SiO2)