Man Made Material, Not A Natural Rock Or Mineral Specimen

Pink Granite

Intrusive Felsic Igneous Rock

Weathered granite or granitic gneiss

Granite: quartz, feldspar, and mica; possibly gneiss if the dark minerals are banded

Polished carnelian-rich agate (likely polyhedral jasper/chalcedony)

Microcrystalline quartz, SiO₂, with iron-oxide inclusions

Rhyolitic Tuff

Rhyolitic Tuff / Pyroclastic rock

Quartz Geode

Silicon Dioxide (SiO2) within a geode

Note: Item is not a geological specimen

n/a

Sandstone

Arenite

River Stone (Quartzite/Siltstone)

Quartzite (primarily SiO2)

Rounded basalt pebble

Basalt, aphanitic mafic volcanic rock; primarily plagioclase and pyroxene with possible olivine

Sandstone (Quartz-rich)

Arenite (composed primarily of SiO2)

Argillite (with Barnacles)

Argillite (metamorphosed mudstone/shale)

Malachite

Malachite — Cu₂CO₃(OH)₂, hydrated copper carbonate

Smoky Quartz with Iron Inclusions

Silicon Dioxide (SiO2)

Tumbled smoky quartz with iron-stained inclusions

Quartz (SiO₂), likely smoky quartz variety

Serpentine

Antigorite/Chrysotile group (Mg3Si2O5(OH)4)

Blue Sapphire (likely costume glass imitation)

Corundum (Al2O3) with iron/titanium impurities

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

Quartzite Geode (unopened)

SiO2 (Silicon Dioxide)

Slag (Industrial Byproduct)

Anthropogenic Vitreous Silicate material

Mother of Pearl (Nacre)

Calcium Carbonate (primarily aragonite, with conchiolin)

Rutilated Quartz

Quartz with Rutile inclusions (SiO2 with TiO2)

Basalt Pebble

Basalt

Unidentified dark pebble

Undetermined; possibly polished basalt, chert, or iron-rich stone

Sandstone

Arenite

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Tumbled brown translucent stone, likely quartz/jasper

Microcrystalline quartz (SiO₂), possibly iron-stained chalcedony or jasper

Turquoise

Turquoise, CuAl6(PO4)4(OH)8·4H2O

Quartz (Citrine / Yellow Quartz)

Silicon Dioxide (SiO2)

Quartz-rich rock with chlorite/epidote vein

Milky quartz with green chlorite or epidote; exact identification requires testing

Siltstone Pebble

Siltstone (fine-grained siliciclastic sedimentary rock)

Polished turquoise

Turquoise — hydrated copper–aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O

Diamond (or Diamond Simulant like Cubic Zirconia)

Carbon (C) - if Diamond; Zirconium dioxide (ZrO2) - if Cubic Zirconia

Chert

Microcrystalline Quartz (SiO2)

Sandstone (Pebble)

Clastic sedimentary rock (SiO2 primary)

Dyed Agate Slice

Silicon Dioxide (SiO2) with artificial colorants

Serpentinite (probable)

Serpentinite, dominated by serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with dark magnetite or chromite and pale carbonate/talc possible

Sandstone

Arenite (SiO2 main component)

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Moss Agate / Chalcedony

Silicon Dioxide (SiO2)

Coquina

Bioclastic Limestone

Polished copper-bearing rock, likely cuprite-rich copper ore

Cuprite (Cu₂O) with native copper and iron-oxide matrix, probable

Shale

Fissile Mudstone (primarily composed of clay minerals and quartz)