Mineral Group

Garnet

Garnet group: X3Y2(SiO4)3 (commonly Almandine-Pyrope series)

Epidote

Epidote Group (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))

Likely polished garnet fragment

Garnet group, possibly almandine (Fe₃Al₂Si₃O₁₂)

Moonstone

Orthoclase Feldspar (specifically showing adularescence)

Basalt

Mafic Volcanic Rock (composed mainly of Plagioclase, Pyroxene, and Olivine)

Serpentinite (likely)

Serpentinite, dominated by serpentine-group minerals (antigorite, lizardite, or chrysotile)

Serpentine (polished/tumbled)

Serpentine-group minerals, chiefly antigorite, Mg₃Si₂O₅(OH)₄

Peridotite (Dunite)

Peridotite / Ultramafic Igneous Rock

Native Silver

Silver (Ag)

Fossilized Gastropod Shell

Gastropoda (Class)

Garnet (likely Almandine or Pyrope)

Garnet (Group Name), Fe3Al2(SiO4)3 or Mg3Al2(SiO4)3

Orthoclase Feldspar (or K-Feldspar)

Orthoclase (KAlSi3O8)

Basalt

Extrusive Igneous Rock

Basalt Pebble

Basalt (Mafic Extrusive Igneous Rock)

Garnet (Almandine)

Almandine (Fe3Al2(SiO4)3)

Serpentine (Serpentinite)

Serpentinite (complex silicate group including lizardite, chrysotile, and antigorite)

Serpentine

Antigorite/Chrysotile group (Mg3Si2O5(OH)4)

Mudstone

Lutylite (group of fine-grained sedimentary rocks)

Sedimentary Strata of the Badlands (Mudstone, Siltstone, and Sandstone)

White River Group (Brule and Chadron Formations)

Basalt

Basalt (principally composed of pyroxene and plagioclase feldspar)

Garnet

Group of silicate minerals (e.g., Almandine: Fe3Al2(SiO4)3)

Blue Apatite

Fluorapatite / Apatite Group Ca5(PO4)3(F,Cl,OH)

Blue Apatite

Fluorapatite / Apatite group (Ca5(PO4)3(F,Cl,OH))

Sunstone

Oligoclase or Andesine (Feldspar Group), (Ca,Na)((Al,Si)4O8)

Garnet

Garnet Group (formula varies, e.g., Almasndine: Fe3Al2(SiO4)3)

Sunstone

Oligoclase (Plagioclase Feldspar Group) - (Ca, Na)(Al, Si)4O8

Garnet

Garnet Group (Silicate Minerals), formula varies e.g., Alm: Fe3Al2(SiO4)3

Serpentinite

Serpentinite (composed primarily of serpentine-group minerals like antigorite, chrysotile, and lizardite; chemical formula varies but generally Mg3Si2O5(OH)4)

Serpentine

Serpentinite (rock), Serpentine group minerals (e.g., Antigorite, Lizardite, Chrysotile)

Polished greenstone (likely serpentine or nephrite-like material)

Serpentine-group minerals, commonly antigorite/lizardite; possible nephrite (actinolite–tremolite amphibole)

Tumbled serpentine (likely)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄

Quartz with Chlorite inclusions

Silicon Dioxide (SiO2) with Chlorite group minerals (hydrous magnesium iron alumino-silicate)

Biotite Mica

Biotite, K(Mg,Fe)3AlSi3O10(F,OH)2

Serpentinite

Serpentinite (composed primarily of Serpentine group minerals, e.g., Lizardite, Chrysotile, Antigorite)

Serpentinite

Serpentinite (composed primarily of Serpentine group minerals like Antigorite, Lizardite, and Chrysotile)

Garnet-bearing granite or pegmatitic granitic rock

Coarse-grained granitoid, likely granite or pegmatite, composed mainly of quartz and feldspar with almandine/spessartine garnet and dark biotite or amphibole

Tumbled green-brown stone, likely serpentine

Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite

Tumbled dark green stone, likely serpentine

Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄)

Likely greenstone (serpentinized rock)

Serpentinite, predominantly serpentine-group minerals [Mg₃Si₂O₅(OH)₄]

Tumbled greenstone (likely serpentine)

Serpentinite; mainly serpentine-group minerals, commonly antigorite, lizardite, or chrysotile

Serpentinite

Serpentinite (composed primarily of Serpentine group minerals such as Antigorite, Lizardite, and Chrysotile)

Serpentinite

Serpentinite (composed primarily of Serpentine group minerals, Mg3Si2O5(OH)4)