Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Category
Browse sedimentary rock (specifically a concretion or possibly a geode) specimens identified by the Rock Identifier community.
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Honey Calcite
Calcium Carbonate (CaCO3)
Blue Calcite
Calcium Carbonate (CaCO3)
Yellow Quartz (Chalcedony/Agate)
Silicon Dioxide (SiO2)
Chert (Jasper)
Microcrystalline Quartz (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz (specifically Quartzite or Massive Quartz)
Silicon Dioxide (SiO2)
Sandstone
Sandstone (various mineral compositions)
Chert (Chert Nodule in Limestone)
Microcrystalline Quartz (SiO2)
Orange Calcite
Calcium Carbonate (CaCO3)
Basalt (Water-worn Pebble)
Mafic Volcanic Rock (High in Fe and Mg)
Scoria (with likely iron oxidation)
Scoria (Basaltic Scoria)
Quartz Vein in Host Rock (Gabbro or Basalt)
Silicon Dioxide (SiO2) with Mafic Silicates
Vesicular Basalt (or Scoraceous Basalt)
Basalt with vesicular texture
Vesicular Basalt (or Scoria)
Vesicular Basalt
Basalt Scoria
Vesicular Basalt
Quartzite River Rock
Quartzite (SiO2)
Quartz (Iron-stained or Milky)
Silicon Dioxide (SiO2)
Quartz (Milky or Cloudy Quartz)
Silicon Dioxide (SiO2)
Green Aventurine
Silicon Dioxide (Quartz variety) with Fuchsite inclusions (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)
Vesicular Basalt (or Scoria)
Basalt (Aphanitic-Vesicular Mafic Igneous Rock)
Orange Calcite (Banded Calcite)
Calcium Carbonate (CaCO3)
Pink Granite
Phaneritic Plutonic Igneous Rock (composed of K-feldspar, Quartz, and Mica)
Dream Amethyst (Chevron Amethyst)
Silicon Dioxide (SiO2) with iron impurities and gamma radiation exposure
Botryoidal Quartz / Calcite Geode crust
Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3)
Greywacke (River Pebble)
Greywacke sandstone with quartz veining
Chevron Amethyst
Silicon Dioxide (SiO2) with iron impurities
Dalmatian Stone
Dalmatian Jasper (Aplitic Perthite)
Green Common Opal
Hydrated Silica (SiO2·nH2O)
Pink Granite
Phaneritic Felsic Igneous Rock (composed primarily of K-Feldspar, Quartz, and Plagioclase)
Orange Calcite
Calcium Carbonate (CaCO3)
Jasper (likely Kambaba or Crocodile Jasper variety)
Silicon Dioxide (SiO2) with inclusions
Amethyst on Agate/Basalt Matrix
Silicon Dioxide (SiO2) with iron impurities
Carnelian Agate
Silicon Dioxide (SiO2) - Variety: Chalcedony
Amethyst
Amethyst (Silicon Dioxide, SiO2)
Granitic Pegmatite
Coarse-grained Granite (KAlSi3O8 + SiO2)
Mookaite Jasper
Radiolarite (Silicon Dioxide, SiO2)
Red Jasper (Chert)
Silicon dioxide (SiO2) with iron oxide inclusions
Chert (varieties include Flint and Jasper)
Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)
Yellow Jasper
Silicon Dioxide (SiO2) with iron hydroxides (Goethite)
Amethyst
SiO2 (Silicon Dioxide)
Chalcedony with Druzy Quartz Geode
Silicon Dioxide (SiO2)