Man Made Material (Simulated Mineral)

Quartz Pebble (with probable inclusions or staining)

Quartz (Silicon Dioxide - SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz / Common Agate

Silicon Dioxide (SiO2)

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (Silicon Dioxide - SiO2)

Amygdaloidal Basalt with Epidote

Amygdaloidal Basalt (Mafic volcanic rock)

Mica-rich schist

Muscovite–biotite schist, commonly quartz-bearing

Petrified Wood

Silicified wood (primarily SiO2)

Arfvedsonite in Matrix

Arfvedsonite [Na3(Fe2+)4Fe3+Si8O22(OH)2]

Mammoth or Mastodon Tooth Fragment

Mammuthus / Mammut molar fragment

Sandstone

Clastic sedimentary rock (primarily SiO2)

Red Sandstone

Arenite (primarily SiO2 with Fe2O3)

Weathered sandstone or iron-stained sedimentary rock

Quartz-rich sandstone, possibly ferruginous sandstone

Sandstone

Arenite

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily Quartz, SiO2)

Polished dendritic jasper or agate slab

Microcrystalline quartz (SiO₂), likely jasper with chalcedony and iron/manganese dendrites

Quartz-rich breccia or vein quartz with dark inclusions

Milky quartz (SiO₂), likely brecciated and cemented with iron oxides and dark mica/amphibole minerals

Sandstone

Clastic Sedimentary Rock

Yellow Calcite

Calcium Carbonate (CaCO3)

Yellow Calcite

Calcium Carbonate (CaCO3)

Petrified Wood

Silicified wood (Quartz, SiO2)

Quartz

Silicon Dioxide (SiO2)

Limonite (Iron Stone Concretion)

Limonite (Hydrous Iron Oxide) - FeO(OH)·nH2O

Garnet-bearing gneiss

Quartz–feldspar–mica gneiss with iron-rich garnet (commonly almandine)

Fossil shell fragment

Likely a fossilized brachiopod or bivalve; exact taxon cannot be determined from the image

Weathered quartz-rich river cobble, possibly quartzite

Quartzite (mostly microcrystalline SiO₂), tentatively identified

Sandstone

Sandstone (SiO2 dominated)

Sandstone

Arenite (SiO2 primarily)

Sandstone

Arenite (SiO2 primarily)

Sandstone

Arenite (primarily Quartz-rich)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Sandstone

Arenite

Gneiss (Banded Gneiss)

Gneiss

Schist

Mica Schist

Quartz-rich hydrothermal ore rock, likely gold-bearing quartz vein

Milky quartz (SiO₂) with iron-oxide staining and probable sulfide minerals; host rock may be schist or altered granite

Sandstone

Arenite (SiO2 primarily)

Sandstone

Arenite (primarily Quartz Arenite)

Sandstone (Quartzose)

Arenite (composed primarily of SiO2)

Sandstone

Arenite/Quartz Arenite

Yellow tumbled/rough chalcedony, possibly citrine or dyed agate

Chalcedony (microcrystalline SiO₂), with yellow coloration likely from iron oxides; exact identification is uncertain from the photograph

Tumbled brown agate or jasper

Microcrystalline quartz, SiO₂ (likely chalcedony/agate with iron oxides)

Clear quartz sphere

Quartz (silicon dioxide, SiO₂), likely rock crystal or low-grade milky quartz