Obsidian
Extrusive igneous volcanic glass (rich in SiO2)
Category
Browse crystal specimens identified by the Rock Identifier community.
Obsidian
Extrusive igneous volcanic glass (rich in SiO2)
Obsidian
Volcanic Glass (SiO2)
Black Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Amethyst
Quartz (Silicon Dioxide with Iron impurities), SiO2
Obsidian
Amorphous Volcanic Glass (primarily SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Smoky Quartz
Smoky Quartz (Silicon Dioxide, SiO2)
Obsidian
Obsidian (Volcanic Glass)
Milky Quartz with Iron Inclusions
Silicon Dioxide (SiO2)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Milky Quartz
Silicon Dioxide (SiO2)
Snowflake Obsidian
Vitreous volcanic silicate rock (SiO2) with Spherulite inclusions
Smoky Quartz (with Druzy/Polished Edge)
Smoky Quartz (Silicon Dioxide, SiO2)
Black Obsidian
Volcanic Glass (SiO2 + impurities)
Milky Quartz Geode or Druzy Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Obsidian
Obsidian (Volcanic Glass)
Black Obsidian
Volcanic Glass (SiO2 + impurities)
Milky Quartz
Silicon Dioxide (SiO2)
Erythrite
Erythrite (Cobalt Bloom) - Co3(AsO4)2·8H2O
Pyrite
Iron Disulfide (FeS2)
Citrine
Crystalline Quartz (SiO2) with iron impurities
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
Orange Calcite
Calcium Carbonate (CaCO3)
Garden Quartz
Included Quartz (SiO2 with accessory minerals such as Chlorite, Hematite, or Feldspar)
Marble
Recrystallized Calcite / Dolomite (CaCO3)
Milky Quartz
Silicon Dioxide (SiO2)
Pyrite Geode
Iron Disulfide (FeS2)
Eudialyte in Matrix
Na15Ca6(Fe,Mn)3Zr3(Si,Nb) (Si25O73) (OH,Cl,H2O)3
Smoky Quartz (Rough Specimen)
Silicon Dioxide (SiO2)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Yellow Quartz (Citrine Quartz)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz (White or Milky Quartz Pebble)
Quartz (Silicon Dioxide, SiO2)
Druzy Quartz
Crystalline Silicon Dioxide (SiO2)
Pyrite in Shale
Iron Sulfide (FeS2) in Argillaceous Shale
Quartz / Quartzite
Silicon Dioxide (SiO2)
Basalt
Mafic volcanic rock (Silicon dioxide 45-52%)