Metamorphic Rock (Specifically A Rock Composed Of Minerals)

Sandstone (with potentially high Feldspar/Arkose content)

Clastic sedimentary rock (SiO2 dominated)

Granite

Granitic intrusive igneous rock

Granite

Phaneritic Felsic Igneous Rock

Arsenopyrite in Quartz/Host Rock

Arsenopyrite (FeAsS)

Red Jasper (specifically Brecciated Jasper)

Silicon Dioxide (SiO2) with Hematite inclusions

Quartz (likely milky/gray variety)

Quartz (SiO₂)

Note: Item is not a geological specimen

n/a

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Basalt (Vesicular)

Vesicular Basalt

Sandstone (Graywacke type)

Clastic Sedimentary Rock (Lithic Sandstone)

Green Aventurine

Quartz variety (SiO2 with inclusions)

Druzy Quartz on Chert/Siltstone

Silicon Dioxide (SiO2) on Microcrystalline Silica/Siltstone matrix

Petrified Wood

Silicified Wood (primarily SiO2)

White Marble (Tumbled)

Recrystallized Calcite (CaCO3)

Moss Agate

Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxides

Ironstone Concretion (Boji Stone/Moqui Marble type)

Goethite/Hematite-encrusted Sandstone Concretion

Tree Agate

Dendritic Chalcedony (SiO2)

Tree Agate (also known as Dendritic Agate)

Silicon Dioxide with inclusions (SiO2 + Mn/Fe)

Quartzite

Quartzite (primarily SiO2)

Basalt-Amugydule (Amygdaloidal Basalt)

Aphanitic Mafic Igneous Rock with Vesicle Infillings

Desert Varnish on Sandstone

Ferromanganese coating on Quartz Arenite

Quartz / Quartzite

Silicon Dioxide (SiO2)

Iron Ore / Ironstone Concretion

Mixture of iron oxide/hydroxide minerals, likely some combination of Hematite (Fe2O3), Goethite (α-FeOOH), and Limonite (a general term for hydrated iron oxides of variable composition) or potentially Bauxite (a mixture of aluminum hydroxides, often with iron oxides, (Al(OH)3) and FeO(OH)). The visual characteristics strongly suggest iron-rich material.

Milky Quartz (with Iron staining)

Silicon Dioxide (SiO2)

Granite

Phaneritic Felsic Igneous Rock

Granite

Granite (Felsic Plutonic Rock)

Granite

Granite (Felsic Plutonic Rock)

Granite

Granite (Phaneritic igneous rock)

Garnet Schist

Almandine-Garnet Mica Schist

Quartz on Host Rock

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite with Iron Oxide cement

Fossilized Coral

Scleractinia (fossil order), primarily Calcium Carbonate (CaCO3)

Bauxite Ore

Hydrated aluminum oxides (e.g., Gibbsite Al(OH)3, Boehmite ̲̲̲̲AlOOH, Diaspore ̲̲̲̲AlOOH)

Turquoise

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

Granite

Phaneritic Igneous Rock (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)

Red Quartzite

Quartzite (primarily SiO2)

Quartzite

Quartzite (primarily SiO2)

Quartzite

Quartzite (primarily SiO2)

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Quartzite

Quartzite (SiO2)

Quartzite

Quartzite (primarily SiO2)

Quartzite

Quartzite (primarily SiO2)