Synthetic (Not A Natural Rock)

Rounded gray-brown cobble, likely weathered sandstone or quartzite

Tentatively quartz-rich sandstone (SiO₂-dominated); exact identification requires hardness and acid tests

Pink Fluorite

Fluorite (Calcium Fluoride) - CaF2

Clear Quartz

Silicon Dioxide (SiO2)

Turquoise

Hydrate phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)

Carved serpentine wing sculpture

Serpentine-group rock, chiefly antigorite/lizardite: Mg3Si2O5(OH)4

Quartzite

Quartzite (primarily SiO2)

Weathered sandstone or iron-stained sedimentary rock

Likely quartz-rich sandstone; exact identification is uncertain from the photograph

Black Onyx

Silicon dioxide (SiO2) with parallel banded structure

Grooved Maun Ball (Maul/Hammerstone-like Concretion)

Calcareous/Ferruginous Concretion in Sandstone Matrix

Pink Granite

Phaneritic intrusive igneous rock (high Potassium-Feldspar)

Granite (specifically Pink Granite)

Phaneritic Plutonic Rock (High Potassium Feldspar Granite)

Ironstone / Limonite Concretion

Hydrated Iron Oxide Rock (FeO(OH)·nH2O with SiO2)

Emerald in Matrix

Beryl (Be3Al2(SiO3)6) embedded in schist or pegmatite host rock

Turquoise in Matrix

Hydrated copper aluminum phosphate, CuAl6(PO4)4(OH)8·4H2O

Turquoise

Hydrated phosphate of copper and aluminium: CuAl6(PO4)4(OH)8·4H2O

Turquoise in Matrix

Hydrated phosphate of copper and aluminium: CuAl6(PO4)4(OH)8·4H2O

Carnelian and White Quartz Bracelet

Silicon Dioxide (SiO2) - specifically Carnelian (Chalcedony) and Rock Crystal/Snow Quartz

Quartz-rich vein rock, likely milky quartz in weathered host rock

Milky quartz (SiO₂), probably with weathered feldspar and iron-oxide staining

Red Granite

Felsic intrusive igneous rock (K-feldspar rich Granite)

Sandstone

Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)

Likely tumbled basalt or dark volcanic rock

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine or iron oxides

Tumbled black-and-white stone, likely dendritic agate or jasper

Cryptocrystalline quartz (SiO₂), possibly chalcedony with manganese-oxide dendrites

Basalt

Basalt (Mafic Aphanitic Igneous Rock)

Chrysocolla in Jasper (Chryso-Jasper)

Cu2-xAlx(H2-xSi2O5)(OH)4·n H2O (Chrysocolla) + SiO2 (Jasper)

River Cobble (Basalt or Greywacke)

Extrusive Mafic Igneous Rock (likely Basalt)

Dyed Agate

Agate (SiO2)

Weathered iron-rich sandstone or ironstone cobble

Ferruginous sandstone/ironstone, chiefly quartz (SiO₂) cemented or stained by iron oxides and hydroxides

Mixed rock and mineral collection

Mixed lithologies; likely quartz, feldspar, basalt, granite, chert, sandstone, and metamorphic rocks

Amygdaloidal Basalt

Basalt with secondary mineral infilling

Turquoise

Turquoise (Hydrated phosphate of copper and aluminium), CuAl6(PO4)4(OH)8·4H2O

Banded limestone or marble

Calcite-dominated carbonate rock; likely banded marble (CaCO₃)

Yellow Ocherous Siltstone (Limonitic Shale)

Limonitic Siltstone / Goethite-rich Sedimentary Rock

Turquoise

Turquoise (Hydrated phosphate of copper and aluminium) CuAl6(PO4)4(OH)8·4H2O

Turquoise

Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)

Piddock bored rock (Boring Stone)

Ichnofossil-bearing Limestone or Mudstone (trace fossils by Pholadidae)

Pink Granite

Phaneritic Felsic Igneous Rock (composed primarily of K-Feldspar, Quartz, and Mica)

Turquoise

Turquoise - CuAl6(PO4)4(OH)8·4H2O

Sandstone (Ferruginous)

Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 staining)

Green Glass Cullet / Recycled Glass

Amorphous Silicon Dioxide (SiO2) with various metal oxides

Turquoise (Green variety)

Hydrous phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O

Rounded weathered granite (granitoid cobble)

Granite, composed mainly of quartz, feldspar, and mica/amphibole

Granite

Phaneritic Felsic Igneous Rock (composed主に of SiO2, Al2O3, K2O, Na2O)