Gneiss (specifically Biotite Gneiss)
Gneiss (high-grade metamorphic rock primarily composed of Silicates)
Category
Browse sedimentary rock (altered) specimens identified by the Rock Identifier community.
Gneiss (specifically Biotite Gneiss)
Gneiss (high-grade metamorphic rock primarily composed of Silicates)
Orange Calcite
Calcium Carbonate (CaCO3)
Septarian Nodule
Septarian concretion (Complex mixture of Siderite/Limestone, Calcite, and Aragonite)
Gneiss (with Quartz-Feldspar vein)
Gneiss (high-grade metamorphic rock) containing Quartz (SiO2) and Feldspar (KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8)
Amethyst
Amethyst (Silicon Dioxide, SiO2)
Carnelian (Red Chalcedony)
Silicon Dioxide (SiO2)
Carnelian
Carnelian (subset of Chalcedony); SiO2 with Iron Oxide impurities
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Clay (as a rock-forming material)
Clay minerals (e.g., Kaolinite group, Smectite group, Illite group, Chlorite group)
Turquoise
Turquoise (Hydrated phosphate of copper and aluminium) - CuAl6(PO4)4(OH)8·4H2O
Epidote in Quartz (Epidosite)
Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
River Stone (likely Siltstone or fine-grained Basalt)
Clastic Sedimentary (Siltstone) or Mafic Igneous (Basalt)
Granite Gneiss
Gneiss (High-grade regional metamorphic rock)
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Amber
Succinite (with formula approximately C10H16O)
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Quartz (with iron oxide staining)
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Chert (varietal: Jasper or Flint likely, but definitive identification is difficult from image)
SiO₂ (silicon dioxide)
Biotite Schist (likely)
Biotite Schist (rock), Biotite (mineral)
Shiva Lingam
Cryptocrystalline Quartz (Jasproid/Sandstone) with Iron Oxide (Fe2O3)
Greywacke (River Slikkenstone)
Greywacke (Impure Sandstone)
Chert (Yellow Jasper variant)
Microcrystalline Quartz (SiO2)
Green Chert (Jasper)
Silicon Dioxide (SiO2)
Chert / Quartz Pebble
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Quartz Druzy on Matrix (likely Agate or Jasper)
Silicon Dioxide (SiO2) with various mineral inclusions
Almandine Garnet
Iron aluminum silicate (Fe3Al2(SiO4)3)
Quartz (Milky and Bull Quartz)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Mookaite Jasper
Silicon Dioxide (SiO2) with iron oxide impurities
Moqui Marble (Shaman Stone)
Ironstone Concretion (Fe2O3) - primarily Hematite or Goethite shell with Sandstone core
Chert (with Liesegang Banding)
Microcrystalline quartz (SiO2)
Chert / Flint
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Jasper
Silicon Dioxide (SiO2)
Chert (Iron-stained)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
Chert (specifically Banded Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
Jasper (specifically Red Jasper or Iron-stained Chert)
Silicon dioxide (SiO2) with iron oxide inclusions
Coquina
Biogenic Limestone (Calcium Carbonate, CaCO3)
Ironstone with Pyrite
Ferruginous Sandstone (Fe2O3) with minor Sulfide minerals (FeS2)