Synthetic Material (Not A Rock Or Mineral)

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide / Chalcedony)

Weathered reddish-brown rock fragment

Probably altered basalt or fine-grained volcanic rock; exact identification requires testing

Gneiss

Gneiss (a rock type, not a specific mineral with a formula)

Brecciated jasper, possibly rainforest jasper

Jasper: microcrystalline to cryptocrystalline quartz, SiO₂, commonly containing hematite, goethite, chlorite, epidote, and other iron- and manganese-bearing minerals

Halite

Sodium Chloride (NaCl)

Tumbled granite or granitic pebble

Granite; primarily quartz, feldspar, and mica (exact variety uncertain from the image)

Tumbled tan pebble, likely sandstone or chert

Uncertain; probable quartz-rich sandstone (SiO₂-bearing)

Quartzite (with Iron Staining)

Metamorphosed Sandstone (mainly SiO2 with Fe2O3/FeOOH impurities)

Serpentinite

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4

Petrified Wood

Silicified Wood (SiO2)

Tumbled serpentinite (likely antigorite-rich serpentine)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, chromite, or brucite

Conglomerate

Conglomerate

Quartzite Pebble

Quartzite (SiO2 with minor impurities)

Unakite

Altered Granite (Epidotized Granite)

Weathered greenstone (likely serpentinite or altered basalt)

Serpentinite-group rock, commonly dominated by serpentine minerals (antigorite/lizardite); exact identification requires testing

Serpentine / Serpentinite (with Weathering Crust)

Serpentinite (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4

Chert (Flint)

Silicon Dioxide (SiO2)

Serpentinite

Serpentinite (composed mainly of Serpentine-group minerals: (Mg, Fe)3Si2O5(OH)4)

Polished rhyolite (likely porphyritic rhyolite)

Rhyolite, composed chiefly of quartz and alkali feldspar with minor plagioclase, biotite, and iron oxides

Banded Iron Formation (BIF) with Quartz

Banded Iron Formation, often composed of alternating layers of hematite (Fe2O3) or magnetite (Fe3O4) and chert (microcrystalline quartz, SiO2)

Quartzite in Conglomerate

Clastic Sedimentary Rock with Silicon Dioxide (SiO2) inclusions

Conglomerate

Conglomerate (clastic sedimentary rock)

Wishing Stone (Basalt or Chert with Quartz Veins)

Basalt or microcrystalline Quartz (Chert) with localized hydrothermal Quartz (SiO2) veining

Fossilized Gastropod Steinkern

Class Gastropoda internal mold

Basalt

Basalt

Unakite

Unakite (Epidotized Granite)

Chert (Jasper/Flint variation)

Chert (SiO2)

Unakite

Unakite (epidote-bearing altered granite; mainly pink potassium feldspar, green epidote, and quartz)

Chert (River Pebble with Liesegang Rings)

Microcrystalline Silicon Dioxide (SiO2)

Chrysotile Asbestos

Mg3Si2O5(OH)4

Quartzite

Quartzite (predominantly SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Basalt

Basalt (Mafic volcanic rock)

Red Jasper with Quartz Vein

Microcrystalline Quartz (SiO2) with Hematite inclusions

Quartzite River Pebble

Metamorphosed Quartz Sandstone (SiO2)

Lepidodendron Plant Fossil

Lepidodendron sp. (Lycopodiophyta)

Rounded dark river pebble

Likely fine-grained basalt or andesite; exact identification requires a fresh surface or tests

Jasper

Silicon dioxide (SiO2)

Serpentinized ultramafic rock with magnesite

Serpentinite, chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with likely magnesite (MgCO₃) and minor chromite/magnetite

Scoria

Scoria (a vesicular basalt or andesite)

Quartzite

Metamorphic quartz rock (SiO2)

Granite (Unakite / Pink Feldspar Granite)

Granite (Plutonic Igneous Rock)