Banded Agate (specifically Moss or River Agate variety)
Cryptocrystalline Quartz (SiO2)
Category
Browse igneous rock specimens identified by the Rock Identifier community.
Banded Agate (specifically Moss or River Agate variety)
Cryptocrystalline Quartz (SiO2)
Yellow Agate
Chalcedony (cryptocrystalline Quartz), SiO2
Yellow Quartz (Iron-Stained Quartz)
Silicon Dioxide (SiO2) with iron oxide inclusions
Chalcedony (Agate)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Pumice
Vesicular volcanic glass (primarily SiO2 with Al2O3)
Pumice
Highly vesicular volcanic glass (unnamed scientific variant: Rhyolitic/Andesitic Pumice)
Greenschist
Greenschist facies rock
River Pebbles and Quartz
Mixed Igneous, Sedimentary, and Metamorphic Rocks (Silicon Dioxide SiO2 dominant)
Greenschist (Greenstone)
Greenschist
Quartz Vein in Host Rock (Gabbro or Basalt)
Silicon Dioxide (SiO2) with Mafic Silicates
Quartz (likely) / Siliceous rock with quartz phenocrysts (if a rock fragment)
Quartz (SiO₂)
Gneiss
High-grade regional metamorphic rock (Foliated)
Greenstone Celt (Polished Stone Axe)
Metamorphosed mafic rock (often Basalt or Diabase)
Gneiss
Metamorphic rock of high-grade regional metamorphism
Blue Lace Agate (Geode/Druzy variant)
Chalcedony (SiO2) with Quartz druzy
Banded Gneiss
Gneiss (High-grade Metamorphic Rock)
Milky Quartz (Water-worn Pebble)
Silicon Dioxide (SiO2)
Smoky Quartz (Vein Quartz)
Quartz (Silicon Dioxide, SiO2)
Carnelian Agate
Chalcedony (Silicon Dioxide, SiO2) with Iron Oxide impurities
Porphyritic Basalt (with Amygdales)
Amygdaloidal Porphyritic Basalt
Greenschist
Greenschist (composed primarily of Chlorite, Actinolite, and Epidote)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Rough Dark Green Sapphire
Corundum (Al2O3)
Quartz (likely Milky Quartz)
Quartz (SiO₂ - Silicon Dioxide)
Lapis Lazuli (Lazurite crystals on Marble)
Lazurite / (Na,Ca)8[(S,Cl,SO4,OH)2|(AlSiO4)6]
Granitic Gneiss
Gneiss (Polymetamorphic Granitic Gneiss)
Quartz Vein in Host Rock (Pebble)
Quartz (SiO2) with sandstone or siltstone matrix
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Pyrite (on host rock/ore)
Iron Sulfide (FeS2)
Blue Sapphire
Corundum (Al2O3)
Granite Pegmatite
Coarse-grained Granite (SiO2 - Aluminum and Alkalies)
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Gneiss (with Quartz-Feldspar vein)
Gneiss (high-grade metamorphic rock) containing Quartz (SiO2) and Feldspar (KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8)
Scoria
Vesicular Basalt / Scoriaceous Basalt
Scoria (Vesicular Basalt)
Vesicular Basalt
Bronzite
MgSiO3 (Enstatite with 10-30% FeSiO3 in solid solution)
Gneiss
Gneiss (Metamorphic rock composed primarily of quartz, feldspar, and mica)
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)