Obsidian
Extrusive igneous volcanic glass (rich in SiO2)
Category
Browse mineral (synthetic glass) specimens identified by the Rock Identifier community.
Obsidian
Extrusive igneous volcanic glass (rich in SiO2)
Obsidian
Volcanic glass
Glass
Amorphous Silicon Dioxide (SiO2)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide)
Polymer Clay (Mock Mineral)
Polyvinyl chloride (PVC) with plasticizers and pigment
Muscovite Mica
Muscovite (Potassium Aluminum Silicate Hydroxide Fluoride), KAl2(AlSi3O10)(OH,F)2
Quartz Pebbles
Silicon Dioxide (SiO2)
Obsidian
Volcanic glass (SiO2-rich extrusive igneous rock)
Quartz (Clear Quartz/Rock Crystal)
Silicon Dioxide (SiO2)
Amethyst (Raw Quartz)
Silicon Dioxide (SiO2) with iron impurities
Cullet Glass (Man-made Glass Slag)
Amorphous Silica (SiO2) with chemical additives
Quartz on Schist
Silicon Dioxide (SiO2) on Foliated Metamorphic Rock
Red Swirl Beads (Likely Resin or Glass, simulating Red Jasper or Agate)
N/A (for the beads as pictured); Red Jasper: SiO2 (Chert variety); Red Agate: SiO2 (Chalcedony variety)
Quartz Geode (with possible Manganese or Goethite coating)
Silicon Dioxide (SiO2)
Black Obsidian
Volcanic Glass (SiO2)
Quartz (Clear Quartz/Rock Crystal)
Silicon Dioxide (SiO2)
Quartz (Milky/Rose variety)
Silicon Dioxide (SiO2)
Quartz (Milky to Clear)
Silicon Dioxide (SiO2)
Snowflake Obsidian
Spherulitic Obsidian (primarily SiO2)
Black Obsidian
Obsidian (Volcanic Glass)
Quartz / Common Opal Transition
Silicon Dioxide (SiO2)
Pumice or Tufa/Travertine
Pumice (if igneous) or Calcareous Tufa (if sedimentary)
Quartz (Druzy)
Silicon Dioxide (SiO2)
Black Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Quartzite and Jasper Pebbles
Quartzite (re-crystallized Quartz) and Cryptocrystalline Quartz (SiO2)
Quartz
Silicon Dioxide (SiO2)
Muscovite Mica
Muscovite (Potassium Mica) KAl2(AlSi3O10)(OH)2
Obsidian
Obsidian (Volcanic Glass)
Green Slag Glass
Cullet (Amorphous Silicon Dioxide with impurities)
Quartz (Clear/White)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Clear Quartz
SiO2 (Silicon Dioxide)
Ferruginous Quartz
Silicon Dioxide (SiO2) with iron oxide inclusions (Limonite/Goethite)
Snowflake Obsidian
Volcanic glass containing Cristobalite (SiO2)
Slag Glass (Cullet)
Amorphous Silicon Dioxide (SiO2) with metal oxide colorants
Fulgurite
Fulgurite (Lechatelierite-rich variety)
Arsenopyrite in Quartz Matrix
Arsenopyrite (FeAsS) with Quartz (SiO2)
Snowflake Obsidian
Hydrated Volcanic Glass (primarily SiO2) with Cristobalite inclusions
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Obsidian
Obsidian (Volcanic Glass)
Obsidian
Obsidian (Volcanic Glass)
Quartz (Drusy/Crystalline)
Silicon Dioxide (SiO2)