Obsidian
Volcanic glass (mainly SiO2 with inclusions)
Category
Browse mineral (variant of quartz) specimens identified by the Rock Identifier community.
Obsidian
Volcanic glass (mainly SiO2 with inclusions)
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)
Petrified Wood
Silicified Wood (SiO2)
Quartz (Druzy or Geode fragment)
Silicon Dioxide (SiO2)
Gneiss (with Quartz and Biotite Mica)
Gneiss
Snowflake Obsidian
Spherulitic Obsidian (SiO2 + impurities)
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)
Jasper with Hematite (Red Jasper)
Silicon Dioxide with Iron Oxide (SiO2 and Fe2O3)
Jasper
Silicon dioxide (SiO2) with iron oxide inclusions
Sandstone (Ferruginous)
Arenite (SiO2 with iron oxide impurities)
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)
Jasper with Quartz inclusions
Silicon Dioxide (SiO2) with varying mineral impurities
Geode (Unopened)
Silica-rich concretion (SiO2)
Sandstone
Arenite (primarily SiO2)
Green Aventurine
Silicon Dioxide (SiO2) with Fuchsite inclusions
Yellow Aventurine (Quartz Quartzite)
Silicon Dioxide with Mica inclusions (SiO2 + KAl2(AlSi3O10)(OH)2)
Red Jasper
Jasper (Silicon Dioxide, SiO2 with Iron Oxide impurities)
Aventurine (specifically Green Aventurine)
Silicon Dioxide (Quartz) with inclusions of Fuchsite; SiO2 + K(Al,Cr)2AlSi3O10(OH)2
Sandstone (Water-worn Cobble)
Arenite (SiO2 based)
Sandstone
Arenite (primarily SiO2)
Sandstone
Arenite (primarily SiO2 - Silicon Dioxide)
Jasper (likely Brecciated or Multi-colored)
Jasper (SiO2)
Sandstone
Arenite (composed primarily of SiO2)
Gneiss (specifically a water-worn pebble)
Gneiss
Diorite
Phaneritic Intrusive Igneous Rock (Intermediate Composition)
Diorite
Phaneritic Intermediate Plutonic Rock (Diorite)
Amethyst (Chevron Amethyst)
Amethystine Quartz (SiO2)
Granite Thin Section
Granitic rock (Phaneritic texture)
Druzy Quartz on Host Rock
Silicon Dioxide (SiO2)
Iron-stained Quartzite / Chert
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Quartz Crystal with Inclusions
Silicon Dioxide (SiO2)
Quartz (Milky/Clear variety)
Silicon Dioxide (SiO2)
Milky Quartz with Iron Staining
Silicon Dioxide (SiO2)
Quartz (Microcrystalline/Chert)
Silicon Dioxide (SiO2)
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
Clear Quartz Crystal
Silicon Dioxide (SiO2)
Quartz (River Cobble)
Silicon Dioxide (SiO2)
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Quartz Vein Rock
Silicon Dioxide (SiO2)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Milky Quartz with Iron Staining
Silicon Dioxide (SiO2)