Sandstone
Arenite (SiO2 primarily)
Category
Browse not a rock (man made origin) specimens identified by the Rock Identifier community.
Sandstone
Arenite (SiO2 primarily)
Gneiss
Gneiss (High-grade Metamorphic Rock)
Sandstone (Quartzose)
Arenite (primarily SiO2)
Limestone
Calcium Carbonate (CaCO3)
Greenstone (Epidote/Chlorite Rich Rock)
Metabasalt (often contains Epidote Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH))
Thunderegg (specifically a Jasper/Agate-filled Geode nodule)
Silicon Dioxide (SiO2) within Rhyolitic Matrix
Sandstone
Clastic sedimentary rock (primarily SiO2)
Quartzite
Quartzite (composed primarily of SiO2)
Pumice
Pumicite
Shale (Ferruginous)
Laminated Mudrock (Siliciclastic Sedimentary Rock)
Fossilized Favosites (Honeycomb Coral)
Favosites (extinct genus of tabulate coral)
Milky Quartz
Silicon Dioxide (SiO2)
Granite
Phaneritic Felsic Igneous Rock
Quartz-veined Siltstone/Greywacke
Clastic Sedimentary Rock with Quartz Infill (SiO2 vein)
Quartz (Milky/Granular)
Silicon Dioxide (SiO2)
Rose Quartz
Silicon Dioxide (SiO2) with trace Titanium or Manganese
Agate (Crazy Lace or Eye Agate)
Silicon Dioxide (SiO2)
Quartz Geode (with possible Manganese or Goethite coating)
Silicon Dioxide (SiO2)
Ironstone Concretion
Siderite or Ferruginous Concretion (FeCO3 or Iron Oxides)
Fossilized Coral
Cnidaria (Anthozoa), often replaced by Calcium Carbonate (CaCO3) or Silica (SiO2)
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) within Matrix
Fossil Shell in Sedimentary Matrix
Bivalvia (fossil) in Calcium Carbonate Matrix
Lapis Lazuli
Lapis Lazuli (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2
Sandstone
Arenite (primarily SiO2)
Shale
Shale (composition varies: primarily clay minerals and quartz)
Weathered Sandstone with Algae Growth
Arenite
Granite
Granite
Quartz Vein in Host Rock (Gabbro or Basalt)
Silicon Dioxide (SiO2) with Mafic Silicates
Sandstone
Clastic sedimentary rock (primarily SiO2)
Biotite Mica
K(Mg,Fe)3AlSi3O10(OH)2
Red Sandstone
Arenite (Ferruginous Sandstone)
Sandstone
Arenite (composed primarily of SiO2)
Snowflake Obsidian (or similar porphyritic volcanic rock)
Obsidian with Spherulites (if glassy), or Porphyritic Rhyolite/Andesite (if crystalline groundmass)
Basalt
Mafic Volcanic Rock (Primarily Plagioclase Feldspar and Pyroxene)
Sandstone (Quartzose)
Arenite (composed primarily of SiO2)
Sandstone (likely Arkose or Quartz Sandstone)
Arenite (SiO2 + varied clasts)
Granite (with Quartz and Mica)
Phaneritic Felsic Igneous Rock
Quartz Druze on Matrix
Silicon Dioxide (SiO2)
Sandstone
Arenite (primarily SiO2)
Limestone with Calcite Veins
Calcium Carbonate (CaCO3)
Amygdaloidal Basalt
Basalt with Secondary Mineral Infillings
Basalt
Basalt (Mafic Extrusive Rock)