Obsidian
Volcanic Glass (comprised primarily of SiO2)
Category
Browse mineraloid (human made geological specimen) specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (comprised primarily of SiO2)
Chert
Chert (microcrystalline quartz, SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
Jasper with Quartz Veining
Silicon Dioxide (SiO2) - Cryptocrystalline Chalcedony
Quartz
Silicon Dioxide (SiO2)
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Quartz Pebble in Sandstone matrix
Quartz Conglomerate (SiO2 matrix)
Geode
Crystalline Quartz in Sedimentary Matrix (SiO2)
Gold-bearing Quartz Vein in Mafic Rock
Hydrothermal Quartz Vein within Greenschist/Amphibolite facies (SiO2 with Au)
Quartz Veinated Sandstone or Siltstone
Silicon Dioxide (SiO2) within a clastic sedimentary matrix
Vesicular Basalt with Epidote/Amygdaloidal Basalt
Amygdaloidal Basalt (Mg, Fe)2SiO4 + Ca2(Al, Fe)3(SiO4)3(OH)
Petrified Wood
Silicified Wood (SiO2 - Silicon Dioxide)
Petrified Wood
Silicified Wood (primarily SiO2)
Llanite (Rhyolite with Blue Quartz)
Porphyritic Rhyolite
Cone-in-cone structure
Cone-in-cone structure
Chert (Jasper/Flint Pebble)
Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Quartz geode or druzy quartz specimen
Quartz, silicon dioxide (SiO₂), likely microcrystalline/drusy quartz coating a host rock
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Granite
Granite (Felsic Plutonic Rock)
Banded Calcite or Travertine
Calcium Carbonate (CaCO3)
Quartz (Milky/Snow)
Silicon Dioxide (SiO2)
White Quartz
Silicon Dioxide (SiO2)
Polished Septarian Nodule
Septarian calcite–aragonite concretion, commonly with barite or celestine
Quartz Geode with Calcite/Siderite
Crystalline Silicon Dioxide (SiO2) with Carbonate inclusions
Quartz Crystal
Silicon Dioxide (SiO2)
Chert (Flint)
Silicon dioxide (SiO2)
Quartz with Iron Staining
Silicon Dioxide (SiO2)
Arfvedsonite in Quartz (also known as Eudialyte/Garnet Syenite variety)
Arfvedsonite [Na3(Fe2+)4Fe3+Si8O22(OH)2] within a silicate matrix
Limonite (also known as Yellow Ochre or Brown Hematite)
Limonite (Hydrated iron oxide-hydroxide, FeO(OH)·nH2O)
Banded Chert (Agate/Jasper blend)
Microcrystalline Quartz (SiO2)
Sedimentary rock with quartz veining
Laminated siltstone or mudstone with hydrothermal quartz veins
Quartz Pebble
Silicon Dioxide (SiO2)
Opalite
Synthetic glass / Opalized glass
Quartz (Clear Quartz Point)
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Quartz
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Jasper
Microcrystalline Quartz (SiO2)
Quartz
Silicon Dioxide (SiO2)
Quartz
Silicon Dioxide (SiO2)