Apache Tear (Obsidian)
Volcanic glass (SiO2 - Silicon Dioxide)
igneous
Category
Amorphous Solid
Browse amorphous solid specimens identified by the Rock Identifier community.
Learn about Amorphous Solid in the encyclopedia
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Quartz Geode
Silicon Dioxide (SiO2)
mineral
White Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Mineraloid
Amber
Fossilized Tree Resin
gemstone
Opal
Hydrated Silica (SiO2·nH2O)
mineraloid
Precious Opal
Hydrated Silica (SiO2·nH2O)
mineral
Smoky Quartz (Apache Tear Variety)
Silicon dioxide (SiO2) - Volcanic Glass
igneous
Pink Opal
Amorphous Hydrous Silica (SiO2·nH2O)
mineral
Obsidian
Volcanic glass (high silica content based on SiO2)
igneous
Petrified Wood
Silicified Wood (SiO2)
fossil
Black Opal (Triplet)
Hydrated Silica (SiO2·nH2O)
mineral
Opal
Hydrated Silica (SiO2·nH2O)
mineral
Rainbow Obsidian
Volcanic glass (SiO2 - approximately 70% or more silicon dioxide)
Igneous
Opal
Hydrated silicon dioxide (SiO2·nH2O)
gemstone
Geode Nodules / Chalcedony Geode
Silicon Dioxide (SiO2) - Amorphous to Cryptocrystalline Quartz
sedimentary
Amber
Succinite (Approximate formula: C10H16O)
Mineraloid
Green Opal
Hydrated Silica (SiO2·nH2O)
mineraloid
Opal (in Jewelry Setting)
Hydrated Silicon Dioxide (SiO2·nH2O)
gemstone
Petrified Wood
Fossilized Wood (silicified wood)
fossil
Opal
Hydrated amorphous silica (SiO2·nH2O)
mineral
Slag (Industrial Byproduct)
Anthropogenic Vitreous Silicate material
igneous
Opal
Hydrated amorphous silica (SiO2·nH2O)
mineral
Shell Cameo
Cypraecassis rufa (Bullmouth Queen Helmet Shell)
mineraloid / biogenic specimen
Opal
Hydrated amorphous silica (SiO2·nH2O)
mineral
Quartz Geode
Silicon Dioxide (SiO2) in sedimentary host rock
sedimentary
Petrified Wood
Silicified wood (primarily quartz, SiO2)
fossil
Porphyritic Andesite or Basalt
Porphyritic Intermediate/Mafic Igneous Rock
igneous
Quartz Geode
Silicon dioxide (SiO2)
mineral
Geode or Concretion
Silica-filled nodule (likely SiO2)
sedimentary
Quartz Geode
Crystalline Silicon Dioxide (SiO2)
mineral
Vesicular Basalt (Lava Rock)
Vesicular Basalt
igneous
Asphalt
Asphalt concrete
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) in Geode form
sedimentary
Vesicular Basalt (Lava Rock)
Vesicular Basalt
igneous
Gold Grain
Native Gold (Au)
mineral
Druzy Quartz on Quartz Base
Silicon Dioxide (SiO2)
mineral
Quartz-filled Basalt Geode
Amygdaloidal Basalt with Quartz (SiO2)
igneous
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Geode (Unopened)
Silica-rich Concretion (SiO2)
sedimentary
Basalt Breccia
Volcanic Breccia (composed of basaltic clasts in a fine-grained matrix)
igneous
Geode (unopened)
Silica-filled Concretion (SiO2)
sedimentary
Black Onyx
Silicon Dioxide (SiO2) with carbon impurities
mineral