Synthetic (Not A Rock Or Mineral)

Sandstone (with possibly iron oxides and other minerals)

Sandstone

Quartz Veined Mudstone

Metasedimentary rock with Quartz (SiO2) veins

Basalt

Basalt (Mafic Extrusive Igneous Rock)

Possible tektite or iron-rich slag-like natural specimen

Uncertain; possibly natural glass (tektite) or magnetite-rich rock

Gneiss

Banded orthogneiss or paragneiss, typically quartz–feldspar–mica bearing

Conglomerate

Clastic Sedimentary Rock

Quartz Crystal Cluster on Matrix

Silicon Dioxide (SiO2)

Agate

Silicon Dioxide (SiO2) - variety Chalcedony

Mixed rock and mineral collection

Multiple specimens; visible examples may include quartz (SiO₂), amethyst (quartz), calcite (CaCO₃), and dark mafic rocks

Mixed Mineral and Rock Collection

Mixed geological specimens (Quartz, Amethyst, Rose Quartz, Jasper, Epidote, Chert)

Slate

Foliated Metamorphic Rock

Gold-bearing Quartz with Iron Oxides

Quartz (SiO2) with Limonite/Goethite (FeO(OH)) and Pyrite (FeS2)

Mixed rock and mineral collection

Multiple specimens; visible pieces may include quartz, calcite, agate/chalcedony, jasper, and dyed or coated materials

Mixed rock and mineral specimen collection

Multiple species, likely quartz (SiO₂), calcite (CaCO₃), feldspar, chert, and assorted volcanic/sedimentary rocks

Unidentified Dark Mineral or Rock

Indeterminate (Likely Silicon Dioxide or Carbon-based)

Mineral and Rock Collection (Assorted)

Mixed collection including Quartz (SiO2), Jasper (SiO2 with impurities), Rose Quartz, and Aventurine

Schist

Mica Schist

Sandstone Pebble

Sedimentary quartz arenite

Granite

Granite (composed primarily of Quartz, Feldspar, and Mica/Amphibole)

Sandstone

Clastic Sedimentary Rock

Sandstone

Sedimentary Clastic Rock

Sandstone (with Siltstone/Greywacke variations)

Sedimentary Rock (Clastic)

River Pebble (Granite/Gneiss)

Granitic Pebble / Quartz-Feldspar Aggregate

Pyrite in Quartz

Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)

Sandstone

Quartzose Sandstone (Sedimentary Rock)

Glauconite (Glauconitic Sandstone)

Glauconite [(K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2]

Granite Pebble

Granite (Plutonic Igneous Rock)

Fossilized Bone

Permineralized Vertebrate Bone

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic volcanic rock)

Quartz Vein in Pelite (Metamorphic Rock)

Hydrothermal Quartz Veining in Metasedimentary Rock (SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Geode half

Geode (often quartz/chalcedony based)

Serpentinite

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4

Desert Varnish on Sandstone

Ferromanganese coating on Quartz Arenite

Gneiss

Gneiss (High-grade metamorphic rock)

Dalmatian Stone

Dalmatian Jasper (Aplite rock composition)

Sandstone (likely Arkosic or Lithic)

Clastic Sedimentary Rock (SiO2 with accessory minerals)

Sandstone with Manganese Staining

Quartz Arenite / Sedimentary Rock

Basalt with Quartz Veining

Veined Basalt (composed primarily of plagioclase feldspar, pyroxene, and olivine with quartz/calcite infill)

Sandstone

Sandstone (various mineral compositions)

Sandstone

Sedimentary Rock (Quartz arenite)

Sandstone Pebble

Arenite (Sandstone)