Selenite (Satin Spar)
Gypsum (CaSO4·2H2O)
Category
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Selenite (Satin Spar)
Gypsum (CaSO4·2H2O)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Petrified Wood
Silicified Wood (SiO2)
Greenstone
Protolith of basalt, diabase, or gabbro; often contains minerals like chlorite, actinolite, and epidote
Red Jasper
Jasper (Silicon Dioxide) - SiO2
Chalcedony (Agate)
Silicon Dioxide (SiO2)
Amethyst
SiO2 (Silicon Dioxide with iron impurities)
Schist
Mica Schist
Muscovite Schist
Muscovite (KAl2(AlSi3O10)(OH)2) in Schist
Pink Sapphire
Corundum (Al2O3 with Chromium/Titanium/Iron traces)
Garnet Schist
Garnetiferous Mica Schist
River Pebble (Brecciated Chert/Siltstone)
Silicon Dioxide (SiO2) with mineral inclusions
Pink Feldspar (Orthoclase)
Orthoclase Feldspar (KAlSi3O8)
Obsidian
Amorphous volcanic glass (SiO2)
Bornite (Peacock Ore)
Bornite (Cu5FeS4)
Pyrite
Iron Disulfide (FeS2)
Ferruginous Sandstone
Sandstone with iron oxide (Hematite/Limonite) cement
Rose Quartz
Quartz (Silicon Dioxide, SiO2)
Milky Quartz Mushroom Carving
Quartz (Silicon Dioxide, SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Chert (Jasper-like Silicate)
Microcrystalline quartz (SiO2)
Banded Rock (likely Quartz-rich)
Uncertain, likely a Metamorphic Rock (e.g., Gneiss or Schist) with prominent Quartz and other minerals
Chert (Flint Nodules)
Microcrystalline Quartz (SiO2)
Chert (specifically Tan Chert)
Chert (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Calcite
Calcium Carbonate (CaCO3)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Banded Iron Formation (BIF) / Iron Ore
Banded Iron Formation (composed primarily of Hematite (Fe2O3) and Magnetite (Fe3O4) with Quartz/Chert)
Fluorite
Calcium fluoride (CaF2)
Milky Quartz Geode Fragment
Silicon Dioxide (SiO2)
Granite
Granitoid
Septarian Nodule (Septarian Stone)
Septarian Concretion (CaCO3 with Siderite/Calcite/Aragonite)
Banded Agate
Cryptocrystalline Quartz (SiO2)
Coral Fossil (Scleractinia)
Scleractinia (Order), primarily CaCO3 (Aragonite or Calcite)
Chert (and Petrified Wood)
Silicon Dioxide (SiO2)
Obsidian with Spherulitic Devitrification (Snowflake Obsidian/Mahogany related)
Volcanic Glass (70% or more SiO2)
Labradorite
Labradorite (Ca,Na)(Al,Si)4O8
Pyrite
Iron Sulfide (FeS2)
Banded Agate
Chalcedony (Silicon Dioxide, SiO2)
Biotite Mica
K(Mg, Fe)3AlSi3O10(F, OH)2