Banded Agate (specifically Sardonyx or Carnelian Agate)
Silicon Dioxide (SiO2) - Chalcedony variety
Category
Browse sedimentary (secondary mineral) within igneous specimens identified by the Rock Identifier community.
Banded Agate (specifically Sardonyx or Carnelian Agate)
Silicon Dioxide (SiO2) - Chalcedony variety
Pyrite (on a metal substrate)
Iron Sulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)
Pyrite
Iron Disulfide (FeS2)
Hematite
Iron(III) oxide (Fe2O3)
Pyrite
Iron Disulfide (FeS2)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Thunderegg (Agetized Geode nodule)
Rhyolitic Agate Nodule (SiO2 filling volcanic cavities)
Sandstone
Arenite (primarily SiO2 - Silicon Dioxide)
Gneiss
High-grade metamorphic rock (Gneiss)
Banded Gneiss
Gneiss
Ironstone Concretion / Limonite Node
Limonite (Hydrated Iron Oxide, FeO(OH)·nH2O) with Goethite/Hematite
Obsidian
Volcanic glass (no mineral formula due to amorphous structure, mostly SiO2)
Chrysocolla
Chrysocolla (Cu,Al)2H2Si2O5(OH)4·nH2O
Gneiss
High-grade regional metamorphic rock (Foliated)
Gneiss (Banded Gneiss)
Gneiss
Precious Opal in Matrix
Hydrated Silica (SiO2·nH2O)
Azurite
Azurite (Cu3(CO3)2(OH)2)
Malachite
Copper carbonate hydroxide [Cu2CO3(OH)2]
Sandstone (likely Arkosic or Quartzose)
Sandstone (SiO2 with inclusions)
White Quartz Pebble
Silicon Dioxide (SiO2)
Chert (specifically Flint or Jasper variant)
Silicon Dioxide (SiO2)
Limestone with Algal/Lichen Colonization
Calcium Carbonate (CaCO3)
Chert (Flint)
Chert (SiO2)
Limestone (specifically Grainstone or Micrite)
Calcium Carbonate (CaCO3)
Quartz (likely Rose Quartz or Milky Quartz based on color)
Quartz (SiO2 - Silicon Dioxide)
Chert Pebble with Quartz Veining
Microcrystalline Quartz (SiO2)
Limestone (Brecciated/Recrystallized)
Calcium Carbonate (CaCO3)
Blue Quartz (Aventurine)
Silicon Dioxide (SiO2) with inclusions of Dumortierite or Magnesio-riebeckite
Gneiss (with Mica and Quartz)
Gneissic Metamorphic Rock
Chert (Green variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Jasper/Flint variant)
Silicon Dioxide (SiO2)
Mica Schist
Mica Schist (primarily Muscovite and/or Biotite composition)
Granite Cobble
Felsic Intrusive Igneous Rock (composed of Quartz, Alkali Feldspar, and Plagioclase)
Staurolite (Fairy Cross)
Staurolite (Fe2+2Al9Si4O23(OH))
Chert (Flint)
Silicon Dioxide (SiO2)
Chert (often called Flint or Jasper based on color)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Gneiss
Gneiss
Bauxite / Iron-rich Laterite
Laterite (principally Al(OH)3, Fe2O3, and SiO2)
Gneiss
Gneiss (High-grade metamorphic rock)
Sunstone and Green Aventurine
Sunstone: (Ca,Na)[(Al,Si)2Si2O8] (Plagioclase Feldspar Group); Green Aventurine: SiO2 (Quartz)
Gneiss
Gneiss