Petrified Wood
Silicified Wood (SiO2)
mineral
Category
Organic (Non Geological)
Browse organic (non geological) specimens identified by the Rock Identifier community.
Quartzite
Quartzite (primarily SiO2)
metamorphic
Limestone
Sedimentary rock composed mainly of calcite (CaCO3)
sedimentary
Small tumbled dark pebble, likely basalt or andesite
Fine-grained mafic/intermediate volcanic rock; commonly basalt (plagioclase + pyroxene ± olivine)
igneous
Quartzite
Metamorphic rock predominantly composed of Quartz (SiO2)
metamorphic
Shale
Shale (clastic sedimentary rock composed of silt and clay-sized particles)
sedimentary
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Conglomerate
Conglomerate (SiO2, Al2O3, Fe2O3, CaCo3)
sedimentary
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
igneous
Rounded quartzite pebble
Quartzite, predominantly crystalline SiO₂
metamorphic
Obsidian
Volcanic Glass (SiO2)
igneous
Obsidian
Volcanic glass (SiO2-rich)
igneous
Fossiliferous Limestone / Petrifaction
Sedimentary rock with fossil inclusions / Calcium Carbonate (CaCO3)
fossil
Stromatolite
Biogenic Sedimentary Rock (composed predominantly of CaCO3)
sedimentary
Quartzite with Garnet
Garnetiferous Quartzite (SiO2 + X3Y2(SiO4)3)
metamorphic
Natural White Pearl
Calcium Carbonate (Aragonite/Calcite) with Conchiolin - CaCO3
mineraloid
Quartzite
Quartzite (primarily SiO2)
metamorphic
Obsidian
Obsidian (Volcanic Glass, SiO2)
igneous
Black Obsidian
Volcanic Glass (SiO2 with impurities)
igneous
Iron-stained quartz/chert pebble
Microcrystalline quartz (SiO₂) with iron-oxide minerals, chiefly goethite/limonite
sedimentary
Grey River Stone (Quartz-rich Quartzite/Siltstone)
Quartzite / Meta-siltstone (primarily SiO2)
Metamorphic (low-grade)
Ferrosilicon Slag (Industrial Vitrified Glass)
Vitreous Silicate Residue
Antropogenic (Man-made industrial byproduct)
Synthetic Resin / Plastic Figurine
Synthetic Polymer (Copolymer of Polyethylene or Resin)
Mineraloid-like Synthetic Material
Gemstone ring, likely emerald and opal
Green beryl (Be₃Al₂Si₆O₁₈), with probable common opal (hydrated amorphous silica, SiO₂·nH₂O)
gemstone
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Rounded reddish sandstone pebble
Quartz-rich sandstone, likely ferruginous arkose or litharenite
sedimentary
Rounded sandstone pebble
Quartz-rich sandstone (primarily quartz, with feldspar and iron-oxide cement)
sedimentary
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Petrified Wood
Silicified Wood (SiO2)
mineral
Petrified Wood
Silicified Wood (SiO2)
mineral
Quartzite
Quartzite (Primary mineral: Silicon Dioxide, SiO₂)
metamorphic
Mahogany Obsidian
Obsidian (SiO2 + Fe2O3)
igneous
Shale or Siltstone
Sedimentary Rock (Siliciclastic)
sedimentary
Obsidian
Obsidian (Volcanic Glass, SiO2)
igneous
Chert (Yellow or Brown Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Polished blue calcite (likely)
Calcite, CaCO₃
mineral
Quartzite
Quartzite (composed primarily of SiO2)
metamorphic
Slag
Ferrous Slag (Amorphous calcium-magnesium-aluminum silicates)
igneous (artificial/anthropogenic)
Petrified Wood
Silicified Wood (SiO2 - Silicon Dioxide)
sedimentary
Fossilized Coral
Rugosa / Scleractinia (Agatized or Calcitized Coral)
fossil
Sandstone with Quartz Crystal Infill
Quartz-cemented quartz arenite
sedimentary
Pearl necklace
Pearl (biogenic calcium carbonate, chiefly aragonite; CaCO₃)
gemstone