Obsidian
Volcanic Glass (SiO2 - Silicon Dioxide with impurities)
igneous
Category
Man Made Alloy (Metallic)
Browse man made alloy (metallic) specimens identified by the Rock Identifier community.
Ferruginous Quartz
Quartz (Silicon Dioxide, SiO2) with iron oxide inclusions
mineral
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Quartz (likely milky/rose quartz variety)
Quartz (SiO2 - Silicon Dioxide)
Mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Quartz Druze
Silicon Dioxide (SiO2)
mineral
Banded Agate (specifically Botryoidal/Orbicular Agate)
Silicon Dioxide (SiO2)
Mineral (variety of Chalcedony/Quartz)
Chert (Nodule)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Plagioclase Feldspar (specifically Albite/Oligoclase)
(Na,Ca)(Si,Al)4O8
mineral
White Precious Opal
Hydrated Silica (SiO2·nH2O)
mineral
Granite Pebble (River Rock)
Phaneritic Felsic Igneous Rock
igneous
Chert (specifically Yellow or River Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Citrine
Silicon dioxide (SiO2)
mineral
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide and clay inclusions
sedimentary
Red Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Amber
Succinite (Formula: C10H16O)
mineral
Banded Calcite (often sold as 'Mexican Onyx' or 'Green Onyx')
Calcite (Calcium Carbonate, CaCO3)
sedimentary
White Quartz Pebble
Quartz (Silicon Dioxide - SiO2)
mineral
Coquina / Fossiliferous Limestone
Fossiliferous Calcarenite (Calcium carbonate, CaCO3)
sedimentary
Aquamarine
Beryllium aluminum silicate (Be3Al2Si6O18)
mineral
River Pebbles (Sandstone and Quartzite)
SiO2 (Quartz) dominated clastic rocks
sedimentary and metamorphic
Lava Rock (Scoria)
Scoria (highly vesicular basaltic rock)
igneous
Chert (Flint Nodules)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert Nodule (with Flint core)
Sedimentary Cryptocrystalline Quartz (SiO2)
sedimentary
Agate (specifically, likely a geode slice or nodule)
Agate (a variety of Chalcedony, with chemical formula SiO2)
Mineral
Jasper Agate
Chalcedony (Silicon Dioxide - SiO2)
mineral
Quartz (Chert/Chalcedony Variety)
Silicon Dioxide (SiO2)
mineral
Sandstone (specifically Cross-bedded Sandstone)
Arenite (composed primarily of SiO2)
sedimentary
Pink Feldspar
Orthoclase (KAlSi3O8) or Microcline
mineral
Sandstone (likely Ferruginous)
Arenite (SiO2 with iron oxide impurities)
sedimentary
Quartzite Arrowhead (Archaeological Lithic)
Recrystallized Quartz (SiO2)
metamorphic
Greenschist
Greenschist (Chlorite Schist)
metamorphic
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
mineral
Granite
Phaneritic Intrusive Igneous Rock (primarily composed of SiO2, Al2O3, K2O, Na2O)
igneous
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Sodalite
Sodalite (Na8Al6Si6O24Cl2)
mineral
Emerald In Matrix
Beryl (Be3Al2Si6O18) with trace Chromium/Vanadium
mineral
Granite
Phaneritic Igneous Rock (composed primarily of Quartz, Feldspar, and Mica)
igneous
Unakite
Epidotized Granite
metamorphic
Quartzite
Quartzite (Primary mineral: Quartz, SiO2)
metamorphic
Petrified Wood
Silicified Wood (primarily Chalcedony/Quartz, SiO2)
sedimentary