Obsidian with Spherulitic Devitrification (Snowflake Obsidian/Mahogany related)
Volcanic Glass (70% or more SiO2)
Category
Browse synthetic polymer (polylactic acid) specimens identified by the Rock Identifier community.
Obsidian with Spherulitic Devitrification (Snowflake Obsidian/Mahogany related)
Volcanic Glass (70% or more SiO2)
Ferruginous Quartz
Silicon Dioxide with Hematite/Limonite inclusions (SiO2 + Fe2O3)
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
Desert Varnish on Sandstone
Ferromanganese coating on Quartz Arenite
Basalt (Vesicular)
Mafic Volcanic Rock (rich in Magnesium and Iron)
Smoky Quartz
Silicon Dioxide (SiO2)
Quartz Druzy (on Calcedony/Quartz base)
Silicon Dioxide (SiO2)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
Yellow Quartz (Citrine or Iron-Stained Quartz)
Silicon Dioxide (SiO2)
Amazonite
Amazonite (Microcline) - K(AlSi3O8)
Serpentinite
Serpentinite (composed primarily of Serpentine group minerals: (Mg,Fe)3Si2O5(OH)4)
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)
White Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Scoria (Vesicular Basalt)
Scoria (Extrusive Igneous Rock)
Granite
Granite (composed mainly of Quartz, Feldspar, and Mica)
Tiger's Eye
Pseudomorph of quartz after crocidolite (SiO2 with iron inclusions)
Moonstone
Adularia (orthoclase) or Albite (plagioclase), a feldspar mineral (KAlSi3O8 or NaAlSi3O8 respectively, often a mixture)
Schorl (Black Tourmaline)
Sodium Iron Aluminum Borosilicate Hydroxide - NaFe2+3Al6Si6O18(BO3)3(OH)3OH
Greywacke
Lithic Sandstone (Greywacke - (SiO2+Al2O3+Fe2O3))
Granite
Granitoid
Quartz Vein Rock
Quartz (Silicon Dioxide, SiO2)
Carnelian Agate
Silicon Dioxide (SiO2) - variety of Chalcedony
Red Jasper
Silicon Dioxide (SiO2)
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide and clay impurities
Puddingstone (Gowganda)
Jasper-clast Polymictic Conglomerate (Gowganda Formation)
Amber
Succinite (Resin)
Amber
Succinite (approximate formula C10H16O)
Note: Item is not a geological specimen
Homo sapiens (Dermal Appendage: Pilus)
Amber
Succinite (Organic Mineraloid) - C10H16O
Ferruginous Quartz (Iron-stained Quartz)
Quartz with Iron Oxide inclusions (SiO2 with Fe2O3)
Ferruginous Sandstone (Ironstone)
Arenite with Iron-Oxide Cement (FeO(OH)·nH2O / Fe2O3)