Chert (Golden/Yellow Variety)
Microcrystalline Silica (SiO2)
Category
Browse metamorphic or sedimentary depending on local grade specimens identified by the Rock Identifier community.
Chert (Golden/Yellow Variety)
Microcrystalline Silica (SiO2)
Banded Agate (specifically Lake Superior Agate or similar)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Bauxite
Bauxite (Al(OH)3, AlO(OH))
Coral Fossil (Favosites type)
Phylum Cnidaria, Class Anthozoa (often CaCO3 - Calcium Carbonate)
Limestone (Brecciated/Recrystallized)
Calcium Carbonate (CaCO3)
Jasper
Silicon dioxide (SiO2) with iron oxide inclusions
Jade (Nephrite or Jadeite)
Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2 - a variety of actinolite, an amphibole mineral); Jadeite (Na(Al,Fe3+)Si2O6 - a pyroxene mineral)
Fossilized Wood (with Coal and Limonite)
Petrified Wood (Silicified or Carbonized Flora)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Chert (Jasper)
Silicon Dioxide (SiO2)
Chalcedony (Common Opal or Agate variant)
Silicon Dioxide (SiO₂)
Herkimer Diamond (Quartz Crystal)
Silicon Dioxide (SiO2)
Muscovite Mica (with Schist)
Muscovite - KAl2(AlSi3O10)(OH)2
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
Schist (Chlorite or Mica-rich)
Chlorite Schist
Magnetite
Magnetite (Fe3O4)
Amethyst
Quartz (SiO2) with trace iron impurities
Petrified Wood
Silicified Wood (SiO2)
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
Chert (Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (or possibly Flint)
Chert (variant: Flint)
Carnelian Agate
Carnelian (Silicon Dioxide, SiO2)
Optical Calcite (Iceland Spar)
Calcite (Calcium Carbonate, CaCO3)
Fuchsite in Quartz
K(Al,Cr)2(AlSi3O10)(OH)2 (Muscovite with Chromium)
Shungite
Non-crystalline carbon (allotrope of carbon)
Moonstone
Orthoclase Feldspar (specifically showing adularescence)
Tiger's Eye
Tiger's Eye (a variety of Quartz, SiO₂)
Ferruginous Sandstone
Clastic sedimentary rock (primarily SiO2 with Fe2O3 cement)
Ferruginous Sandstone (Ironstone Nodules)
Ferruginous Sandstone with Limonite/Goethite coating (Fe2O3·H2O)
Red Siltstone (or Red Shale)
Clastic Sedimentary Rock (Composition: primarily Quartz, Clay minerals, and Hematite Fe2O3)
Ferruginous Sandstone with Ironstone Concretion
Goethite-rich Sandstone (FeO(OH))
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)
Fluorite in Matrix
Fluorite (CaF2) within a host rock matrix
Amber (Cherry or Red variety)
Succinite (with various trace amounts of organic compounds)
Quartz Geode
Silicon Dioxide (SiO2)
Rhodochrosite
Manganese carbonate (MnCO3)
Limonite (Iron Stone/Goethite)
Limonite (mixture of hydrated iron oxides, primarily Goethite: α-FeO(OH))
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Clear Quartz Crystal Cluster
Silicon Dioxide (SiO2)