Obsidian
Volcanic glass (high silica content based on SiO2)
igneous
Category
Industrial Byproduct (Often Mistaken For Obsidian Or Mineral)
Browse industrial byproduct (often mistaken for obsidian or mineral) specimens identified by the Rock Identifier community.
Learn about Industrial Byproduct (Often Mistaken For Obsidian Or Mineral) in the encyclopedia
View all →
Obsidian
Volcanic Glass (SiO2 rich)
igneous
![Blue Quartz (Dumortierite Quartz) (SiO2 containing inclusions of Dumortierite [Al7(BO3)(SiO4)3O3]) — metamorphic](https://media.rock.id/blue-quartz-dumortierite-quartz-72e42d24-fbdb-4e3d-bc4b-9cfae9e59260-thumbnail.jpg)
Blue Quartz (Dumortierite Quartz)
SiO2 containing inclusions of Dumortierite [Al7(BO3)(SiO4)3O3]
metamorphic
Sodalite
Na8(Al6Si6O24)Cl2
mineral
Pyrite
Iron Disulfide (FeS2)
mineral
Ironstone Concretion / Limonite-stained Siltstone
Ironstone (primarily Limonite FeO(OH)·nH2O and Siltstone)
sedimentary
Obsidian
Obsidian (Amorphous volcanic glass, SiO2 rich)
igneous
Limonite Concretion (Goonie or Rattlestone)
Limonite (FeO(OH)·nH2O)
sedimentary
Snowflake Obsidian
Volcanic Glass with Spherulitic Cristobalite Inclusion
igneous
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
igneous
Sandstone Chert Concretion
Silica-cemented Concretion (primarily SiO2)
sedimentary
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Black Obsidian and Hematite
Volcanic Glass (SiO2) and Hematite (Fe2O3)
igneous and mineral
Quartz (Iron-Stained)
Silicon Dioxide (SiO2)
mineral
Dendritic Agate (Tree Agate)
Chalcedony (Silicon Dioxide, SiO2) with Manganese or Iron Oxide inclusions
mineral
Ferruginous Quartz
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
mineral
Flower Agate
Chalcedony with Opaque Spherulitic Inclusions (SiO2)
Mineral
Quartz with Iron Staining
Silicon Dioxide (SiO2) with iron oxide impurities
mineral
Blue Apatite
Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)
mineral
Dendritic Opal
Opalized Chalcedony with Manganese Inclusions (SiO2 · nH2O)
mineral
Ferruginous Sandstone (Gozzan/Ironstone)
Arenite with Limonite/Goethite cement (FeO(OH)·nH2O)
sedimentary
Vesicular Basalt with Epidote/Amygdaloidal Basalt
Amygdaloidal Basalt (Mg, Fe)2SiO4 + Ca2(Al, Fe)3(SiO4)3(OH)
igneous
Chrysoprase
Silicon dioxide with nickel impurities (SiO2 + Ni)
mineral
Rhodonite
Manganese Silicate (Mn,Fe,Mg,Ca)SiO3
mineral
Snowflake Obsidian
Volcanic glass containing Spherulites (SiO2)
igneous
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
mineral
Diorite
Phaneritic Intermediate Igneous Rock
igneous
Chert Concretion / Nodule
Microcrystalline Quartz (SiO2)
sedimentary
Specular Hematite (Specularite)
Iron Oxide (Fe2O3)
mineral
Obsidian
Obsidian (volcanic glass, amorphous silica rich rock)
Igneous
Quartz Pebble (Sea Glass-like Quartz)
Quartz (Silicon Dioxide - SiO2)
mineral
Quartzite
Quartzite (SiO2)
metamorphic
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)
igneous
Black Obsidian
Volcanic Glass (Amorphous Silicon Dioxide, SiO2)
igneous
Quartz with Chalcopyrite
Silicon Dioxide (SiO2) with Copper Iron Sulfide (CuFeS2)
mineral
Green Aventurine
Silicon dioxide (SiO2) with inclusions of Fuchsite mica
metamorphic
Pyrite
Iron Sulfide (FeS2)
mineral
Blue Quartz (specifically Dumortierite Quartz)
Silicon Dioxide (SiO2) with inclusions of Dumortierite (Al7BO3(SiO4)3O3)
metamorphic
Horse Chestnut (Buckeye seed)
Aesculus hippocastanum seed
Organic (Non-geological)
Blue Apatite
Apatite, Ca5(PO4)3(F,Cl,OH)
mineral
Apache Tear (Obsidian)
Volcanic Glass (Amorphous Silicon Dioxide)
igneous
Ironstone Concretion / Limonite
Goethite and Limonite (FeO(OH)·nH2O)
sedimentary