Basalt
Basalt (Mafic Extrusive Igneous Rock)
igneous
Category
Not A Rock Or Mineral
Browse not a rock or mineral specimens identified by the Rock Identifier community.
Granite (Dioritic or Hornblende-rich)
Phaneritic Plutonic Felsic to Intermediate Igneous Rock
igneous
Red Sandstone (Iron-rich)
Ferruginous Sandstone (variable formula, primarily SiO2 + Fe2O3)
sedimentary
Serpentinite
Serpentinite (composed primarily of Serpentine group minerals like Antigorite, Lizardite, and Chrysotile)
metamorphic
Obsidian
Volcanic glass (SiO2-rich extrusive igneous rock)
igneous
Mica Schist
Mica Schist (KAl2(AlSi3O10)(OH)2 / K(Mg,Fe)3AlSi3O10(OH)2)
metamorphic
Fossiliferous Limestone (Coquina)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Sandstone (Quartzose)
Arenite (Formula: SiO2 primary, with various cements)
sedimentary
Shale
Fissile Clay-dominant Mudrock (SiO2, Al2O3, K2O, Na2O, CaO, MgO)
sedimentary
Sandstone (Ferruginous)
Arenite (Fe-rich)
sedimentary
Tree Agate
Silicon Dioxide with Chlorite inclusions (SiO2)
Mineral (Variety of Chalcedony)
Sandstone (Ferruginous)
Sandstone (SiO2 with iron oxide inclusions)
sedimentary
Sandstone (Ferruginous)
Arenite (with Hematite/Limonite cement)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Goldstone (Red)
Aventurine Glass
Man-made material (Simulated Mineral)
Ironstone Concretion (Moqui Marble)
Iron Oxide Concretion (Fe2O3 / FeO(OH) mixed with SiO2)
sedimentary
Granodiorite or Diorite
Granodiorite / Diorite
igneous
Diorite
Diorite (Intermediate intrusive igneous rock)
igneous
Quartzite
Quartzite (Primary mineral: Silicon Dioxide, SiO2)
metamorphic
Calamites (Fossilized Horsetail)
Calamites suckowii (Family: Calamitaceae)
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Geode (unopened)
Silica-filled Concretion (SiO2)
sedimentary
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Red Sandstone (Old Red Sandstone Pebble)
Arenite with iron oxide (Fe2O3) cement
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone
Arenite
sedimentary
Banded Flint (Polished Stripe Flint)
Silicon Dioxide (SiO2) - variety of Chert
sedimentary
Red Sandstone
Arenite (Ferruginous Sandstone)
sedimentary
Basalt with Iron Oxidation
Extrusive Mafic Igneous Rock (composed of Plagioclase and Pyroxene)
igneous
Herkimer Diamond
Double-Terminated Quartz (SiO2)
mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Smoky Quartz on Matrix
Silicon Dioxide (SiO2) with trace impurities and aluminum inclusions
mineral
Red Sandstone
Arenite (ferruginous sandstone)
sedimentary
Orthoclase (Potassium) Feldspar in Quartz
KAlSi3O8 (Potassium Aluminum Silicate)
igneous
Garnet-Bearing Gneiss
Almandine-Garnet Gneiss
metamorphic
Graphic Granite (Zebra Rock)
Pegmatitic Granite (composed of Quartz and K-Feldspar)
igneous
Milky Quartz (with Iron Oxide staining)
Quartz (Silicon Dioxide - SiO2)
mineral
Clear Quartz (Crystal Quartz)
Silicon Dioxide (SiO2)
mineral
Agate and Amethyst (Quartz variants)
Silicon Dioxide (SiO2) - Microcrystalline Quartz and Crystalline Quartz
mineral
Basalt with Quartz/Quartzite Veins
Aphanitic Mafic Volcanic Rock with Siliceous Infillings
igneous
Milky Quartz with Iron Inclusions
Quartz (Silicon Dioxide, SiO2)
mineral
Gneiss (specifically Micaceous Gneiss)
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic