Mineral, Possibly Rock Fragment Containing A Mineral

Milky quartz (rough quartz specimen)

Quartz, silicon dioxide (SiO₂)

Likely weathered iron-rich stone

Uncertain; possibly limonite/goethite-bearing rock

Quartz Geode fragment

Crystalline Silicon Dioxide (SiO2)

Bull Quartz with Mica and Host Rock

Massive Quartz (SiO2) with Muscovite/Chlorite inclusions

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic extrusive volcanic rock with secondary mineral infilling)

Pebble / Rounded Rock

Lithic fragment / Water-worn rock

Shale

Shale (Lutite)

Tumbled or cut iron-rich mineral specimen

Likely limonite/goethite (hydrated iron oxides), possibly weathered hematite

Shale

Argillaceous sedimentary rock

Garnet Gneiss

Gneiss containing almandine-pyrope garnet

Pebble

Lithic fragment / Rounded rock fragment

Garnet in Schist (Mica Schist with Garnet Inclusion)

Garnetiferous Mica Schist (X3Al2(SiO4)3)

Likely galena-bearing ore specimen

Galena (PbS), possibly with quartz or calcite gangue

Quartz Crystal Fragment

Silicon Dioxide (SiO2)

Fossilized oyster or bivalve shell

Fossil Gryphaeidae or Ostreoidea; calcitic shell, CaCO₃

Fragmented Sedimentary Pebble

Clastic Sedimentary Specimen

Turquoise

Turquoise - CuAl6(PO4)4(OH)8·4H2O

Porphyritic Basalt

Porphyritic Basalt (containing Plagioclase phenocrysts)

Basalt

Mafic extrusive igneous rock

Quartz (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Iron-rich meteorite candidate

Undetermined meteoritic iron–nickel material; possibly an ordinary chondrite or weathered iron meteorite

Greenstone, likely serpentinite

Serpentinite; predominantly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), possibly with chlorite, talc, magnetite, or antigorite

Garnet-bearing Quartzite

Metamorphic rock containing Almandine Garnet (Fe3Al2(SiO4)3) and Quartz (SiO2)

Limonitic Sandstone with Inclusion

Limonitic Quartz Sandstone (primarily SiO2 with FeO(OH)·nH2O)

Sandstone

Arenite

Mica Schist

Muscovite/Biotite Schist

Weathered sandstone fragment

Quartz-rich sandstone, likely arkose or lithic sandstone

Weathered granitic rock

Granitoid, likely biotite granite or granodiorite

Likely weathered mica schist fragment

Mica schist, chiefly muscovite/biotite mica with quartz and feldspar

Weathered quartz-rich granitoid (likely granite or granodiorite)

Granite–granodiorite; chiefly quartz (SiO₂), feldspar, and minor mica/amphibole

Green Opal (Prase Opal)

SiO2 · nH2O (Hydrated Silicon Dioxide)

Schist

Mica Schist

Metallic sulfide-bearing rock, possibly galena-rich ore

Likely galena (PbS) with iron sulfides and quartz/rock matrix; exact identification requires testing

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Weathered basalt or mafic volcanic rock

Basalt; primarily plagioclase feldspar, pyroxene, and possibly olivine

Quartz Druzy (Geode Fragment)

Silicon Dioxide (SiO2)

Gravel or Crushed Stone

Fragmented Aggregate Stone

Fossiliferous limestone with brachiopod or bryozoan fossils

Calcite (CaCO₃) limestone containing marine invertebrate fossils, possibly brachiopoda or bryozoa

Possible fossilized ammonite or concretion

Indeterminate fossil specimen; possibly an ammonoid mold/cast in iron-rich sedimentary rock

Milky quartz (likely quartz-rich vein fragment)

Quartz, silicon dioxide (SiO₂)

Tumbled quartz-rich stone, possibly blue quartz or granite

Quartz (SiO₂), with probable feldspar and dark accessory minerals

Shale and Pebble Fragment

Sedimentary Rock (Mudstone/Shale with Silica Pebble)