Precious Opal
Hydrated Silica (SiO2·nH2O)
Category
Browse sedimentary like (industrial composite) specimens identified by the Rock Identifier community.
Precious Opal
Hydrated Silica (SiO2·nH2O)
Sandstone
Arenite (primarily Quartz, SiO2)
Blue Sapphire
Corundum (Al2O3)
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
Sandstone Pebble
Arenite (primarily SiO2)
Sandstone (Ferruginous)
Arenite (with Iron Oxide)
Quartzite Pebble
Quartzite (SiO2)
Sandstone
Arenite
Garnet Rhyolite
Rhyolite (high-silica volcanic rock) with almandine/spessartine garnet
Sandstone
Arenite (SiO2 based with primary clasts 0.0625 to 2 mm)
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
Orange Quartz (Citrine Quartz variety)
Silicon Dioxide (SiO2)
Basalt
Basalt (Aphanitic Mafic Igneous Rock)
Ruby
Corundum (Al2O3 with Chromium trace elements)
Basalt
Basalt (Aphanitic Mafic Igneous Rock)
Mica Schist
Mica Schist (primarily Muscovite or Biotite sheet silicates)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Basalt
Extrusive Mafic Igneous Rock (composed primarily of plagioclase, pyroxene, and olivine)
Sandstone (Micaceous)
Arenite (composed primarily of SiO2)
Sandstone (Quartzose)
Arenite (primarily SiO2)
Raw Diamond
Diamond (pure Carbon, C)
Smoky Quartz (Tumbled)
Smoky Quartz (Silicon Dioxide - SiO2)
Fluorite (often called Rainbow Fluorite or Purple-Green Fluorite)
Calcium Fluoride (CaF2)
Garnet-Bearing Schist
Almandine Garnet Micaceous Schist
Vesicular Basalt with Oxidation
Scoriaceous Olivine Basalt (Mafic volcanic rock)
Mica Schist
Crystalline Schist (often primarily Muscovite or Biotite sheet silicates)
Terracotta (Man-made ceramic brick fragment)
Baked clay / High-iron ceramic (Silicate-based ceramic)
Limonite Concretion
Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)
Shale
Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)
Jasper
Silicon dioxide (Microcrystalline Quartz, SiO2)
Petrified Wood
Silicified Wood (SiO2)
Quartzite
Quartzite (primarily SiO2)
Epidote (or Epidote-rich rock)
Epidote. Mineral formula: Ca2(Al,Fe)3(SiO4)3(OH).
Sandstone (Quartzose)
Arenite (primarily SiO2)
Chert (Common Opal/Jasper transition)
Silicon Dioxide (SiO2)
Chert
Chert (Microcrystalline Quartz)
Pink Granite
Phaneritic intrusive felsic igneous rock
Quartz Pebble
Crystalline Silicon Dioxide (SiO2)
Quartz (Float/Abraded)
Quartz (SiO₂)
Ruby
Corundum (Aluminum Oxide with Chromium traces), Al2O3:Cr
Red Garnet
Pyrope-Almandine series (Mg3Al2(SiO4)3 to Fe3Al2(SiO4)3)
Chert (variations include Flint/Jasper)
Microcrystalline or Cryptocrystalline Quartz (SiO2)