Black Spinel
Magnesium Aluminum Oxide (MgAl2O4)
Category
Browse tektite (natural glass) specimens identified by the Rock Identifier community.
Black Spinel
Magnesium Aluminum Oxide (MgAl2O4)
Pumice
Pumice (Amorphous volcanic glass)
River Quartz (Milky and Smoky mix)
Silicon Dioxide (SiO2)
Yellow Quartz (Citrine Quartz Pebble)
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Pumice
Pumice (a highly vesicular extrusive igneous rock)
Smoky Quartz
Quartz (Silicon Dioxide, SiO2)
Amethyst
Amethyst (Silicon Dioxide - SiO2 with iron impurities)
Obsidian
Obsidian (volcanic glass), predominantly amorphous SiO₂
Smoky Quartz with Iron Inclusions
Silicon Dioxide (SiO2)
Halite (Himalayan Pink Salt)
Halite - NaCl (Sodium Chloride)
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily Quartz - SiO2)
Rough Sapphire
Corundum (Al2O3)
Sandstone (Weathered)
Arenite (primarily SiO2)
Sandstone
Arenite
Smoky Quartz
SiO2 (Silicon Dioxide with aluminum impurities)
Sandstone (Quartz Sandstone)
Clastic sedimentary rock (primarily SiO2)
Yellow Quartz (Citrine appearance)
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Yellow Quartz (Citrine type/Tumbled Quartz)
Silicon Dioxide (SiO2)
Granite
Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)
Blue Sapphire
Corundum (Al2O3 with trace amounts of iron and titanium)
Jasper in Quartz (River Cobble)
Silicon Dioxide (SiO2) with Ferric Iron inclusions
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Amethyst
Amethyst (Silicon Dioxide with iron impurities), SiO2
Citrine
Silicon dioxide (SiO2)
Smoky Quartz in Matrix
Silicon dioxide (SiO2) within Pegmatite/Gneiss
Smoky Quartz (Rough Specimen)
Silicon Dioxide (SiO2)
Amethyst
Silicon dioxide (variant with ferric iron impurities), SiO2
Sandstone (likely Ferruginous)
Arenite (SiO2 based with Fe2O3/FeO(OH) cement)
Celestine (Celestite)
Strontium sulfate (SrSO4)
Oolitic Chert
Silicon Dioxide (SiO2) with oolitic texture
Diamond (Set in jewelry)
Cubic Carbon (C)
Smoky Quartz Cluster
Smoky Quartz (Silicon Dioxide - SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Amethyst
Amethyst (Silicon Dioxide, SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Red Quartzite River Pebble
Quartzite (SiO2 with iron oxide inclusions)