Greenstone
Greenschist (composed of actinolite, chlorite, and epidote)
Category
Browse igneous rock (volcanic glass) specimens identified by the Rock Identifier community.
Greenstone
Greenschist (composed of actinolite, chlorite, and epidote)
Goldstone (Red)
Aventurine Glass
Sandstone
Arenite (SiO2 based with mineral cement)
Granite Pebble
Granite (composed primarily of Quartz SiO2, Feldspar KAlSi3O8, and Mica)
Quartz Veinated Sandstone or Siltstone
Silicon Dioxide (SiO2) within a clastic sedimentary matrix
Amphibolite
Amphibolite
Olivine (Peridot)
Olivine (Magnesium Iron Silicate, (Mg,Fe)2SiO4)
Milky Quartz
Silicon Dioxide (SiO2)
Carnelian (Red Chalcedony)
SiO2 (Silicon Dioxide with Iron Oxide impurities)
River Stone (Basalt or Siltstone with banding)
Polished Basaltic or Siliciclastic River Cobble
Diorite (River Cobble)
Intrusive Igneous Diorite
Geode with Quartz/Chalcedony
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
Sandstone (Quartzite Pebble)
Arenite (primarily SiO2)
Banded Agate (Tumbled)
Cryptocrystalline Quartz (SiO2)
Sparkling Druzy Quartz on Matrix
Silicon Dioxide (SiO2) with iron oxide inclusions
Carnelian Agate
Carnelian (Silicon Dioxide: SiO2)
Banded Agate (Botswana Agate)
Silicon Dioxide (SiO2)
Geode Nodules / Chalcedony Geode
Silicon Dioxide (SiO2) - Amorphous to Cryptocrystalline Quartz
Ethiopian Fire Opal
Hydrated Silica (SiO2·nH2O)
Opal
Hydrated Silica (SiO2·nH2O)
Clear Quartz Crystal (Herkimer Diamond style)
Silicon Dioxide (SiO2)
Sandstone
Arenite (composed primarily of SiO2)
Quartz
Quartz (SiO₂ - Silicon Dioxide)
Quartzite
Quartzite (SiO2)
Quartzite River Stone
Quartzite (SiO2)
Pink Quartzite Pebble
Metamorphic Quartzite (SiO2 with iron oxide inclusions)
Rough Star Sapphire (Corundum)
Al2O3 (Aluminum Oxide)
Gold Ore
Native Gold in Quartz (Au)
Quartzite
Quartzite (SiO2)
Granite
Granite (Phaneritic Quartz-Feldspar Felsic Rock)
Milky Quartz
Silicon Dioxide (SiO2)
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Quartz (Float/Abraded)
Quartz (SiO₂)
Common Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Quartz (Smoky/Grey variety)
Silicon Dioxide (SiO2)
Greenstone
Greenschist-facies basaltic rock
Red Garnet (likely Almandine or Pyrope)
Garnet group: X3Y2(SiO4)3 (e.g., Almandine: Fe3Al2Si3O12)
Chert (Jasper variation)
Silicon dioxide (SiO2)
Quartz (Milky/Common)
Silicon Dioxide (SiO2)
Chert / Flint
Microcrystalline Quartz (SiO2)