Basalt
Mafic volcanic rock (dominated by Plagioclase and Pyroxene)
Category
Browse sedimentary like (industrial composite) specimens identified by the Rock Identifier community.
Basalt
Mafic volcanic rock (dominated by Plagioclase and Pyroxene)
Sandstone (Ferruginous/Banded)
Clastic Terrigenous Sandstone (SiO2 with Fe2O3 cement)
Petrified Coral Fossil
Rugose or Tabulate Coral (Hexagonaria or similar fossilized cnidarian)
Petrified Wood
Silicified Wood (primarily SiO2)
Sandstone
Arenite (SiO2 based with cement)
Chert (Jasper)
Silicon Dioxide (SiO2)
Basalt
Basalt (Mafic volcanic rock)
Chert (Jasper/Agate mix)
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (primarily Quartz / Chalcedony: SiO2)
Sandstone (Ferruginous)
Clastic Sedimentary Rock (SiO2 with Fe2O3/FeOOH cement)
Crazy Lace Agate
Silicon Dioxide (SiO2)
Tumbled blue glassy mineral, possibly sodalite or blue aventurine
Identification uncertain; likely sodalite (Na₈Al₆Si₆O₂₄Cl₂) or blue-dyed quartz/slag-like material
Mica Schist
Mica Schist (Quartz-Biotite-Muscovite Schist)
Ruby (Corundum)
Al2O3 (Aluminium oxide with Chromium impurities)
Diamond (Green tinted)
Carbon (C) with trace impurities or lattice defects
Chert (containing Fossil Inclusions)
Microcrystalline Quartz (SiO2)
Shale
Shale (Lutite)
River Quartz Pitting/Cobble
Silicon Dioxide (SiO2)
Fluorite
Calcium fluoride (CaF2)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Satin Spar (often marketed as Selenite)
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
Conglomerate
Sedimentary Conglomerate
Conglomerate
Conglomerate (clastic sedimentary rock)
Anthracite Coal
Anthracite
Quartz Geode
Crystalline Silicon Dioxide (SiO2) in a Geode
Sandstone (Quartzose)
Arenite (primarily SiO2)
Sandstone
Arenite
Plume Agate or Moss Agate
Agate (SiO2)
Garnet Schist
Almandine-Garnet Mica Schist
Orange Calcite
Calcium Carbonate (CaCO3)
Black Tourmaline (Schorl)
NaFe2+3Al6(BO3)3Si6O18(OH)4
Amethyst cluster
Quartz, SiO₂; purple coloration is caused mainly by iron-related defects and natural irradiation
Diabase (Greenstone)
Diabase (also known as Dolerite)
Chert (Jasper-like Silicate)
Microcrystalline Quartz (SiO2)
Quartz (Chert / Agate / Chalcedony)
Silicon Dioxide (SiO2)
Black Tourmaline (Schorl)
Schorl (NaFe2+3Al6(BO3)3Si6O18(OH)4)
Mixed collection of Quartz varieties, Chalcedony, and metamorphic pebbles
Mixed gemstones (primarily Silicon Dioxide - SiO2)
Chert (Jasper/Opaline variety)
Silicon Dioxide (SiO2)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Banded Iron Formation (BIF) with Quartz
Banded Iron Formation, often composed of alternating layers of hematite (Fe2O3) or magnetite (Fe3O4) and chert (microcrystalline quartz, SiO2)