Biogenic Material

Epidote-rich rock (likely epidotite or altered basalt)

Epidote, Ca₂(Al,Fe³⁺)₃(SiO₄)₃(OH); possibly epidote-bearing mafic rock

Sandstone

Arenite (primarily SiO2)

Garnet Schist

Garnetiferous Mica Schist

Coquina or Fossiliferous Limestone

Fossiliferous Calcarenite (CaCO3)

Jasper / Chert (Red)

Cryptocrystalline quartz (SiO2)

Tumbled cream-colored pebble

Likely quartz-rich sandstone or limestone; exact identification requires testing

Rough amethyst-bearing quartz specimens

Quartz, SiO₂; purple coloration from trace iron and irradiation

Tumbled yellow-brown stone, likely quartzite or chalcedony

Quartz-rich rock; predominantly microcrystalline quartz (SiO₂), identification uncertain from image alone

Cubic Zirconia

Zirconium dioxide (ZrO2)

Petrified Wood (Jet or Coalified Wood appearance)

Silicified wood (principally SiO2) or Carbonized Wood

Petrified Wood

Silicified Wood (primarily Quartz/Chalcedony, formula SiO2)

Weathered quartz-rich rock or fossil fragment

Indeterminate; likely quartz-bearing sandstone or siliceous fossil material

Fossilized Bone Fragment

Petrified Osseous Material

Slag (Industrial Glass/Glassy Rock)

Anthropogenic Vitreous Material

N/A - Image does not contain a rock or mineral

Anthropogenic textile material

Polished white-and-brown chalcedony (likely agate/jasper)

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide staining or jasperous inclusions

Limestone

Sedimentary Calcium Carbonate (CaCO3)

Orbicular Granite (specifically Mustard or Yellow Tonalite/Granodiorite)

Orbicular Quartz Diorite / Tonalite

Limestone (Weathered)

Sedimentary Carbonate Rock (CaCO3)

Yellow faceted gemstone, likely citrine or synthetic glass

Citrine (quartz, SiO₂) is the leading natural possibility; visual identification is uncertain from the photograph

Polished botryoidal jasper/chalcedony (likely ocean jasper)

Microcrystalline quartz, SiO₂, with iron-oxide and other mineral inclusions

Brown chalcedony (likely jasper or petrified wood fragment)

Microcrystalline quartz, SiO₂; brown coloration likely from iron oxides

Tumbled orange chalcedony or common opal

Microcrystalline quartz (SiO₂), possibly hydrated silica opal (SiO₂·nH₂O)

Tumbled brown stone, possibly chert or iron-stained quartzite

Indeterminate from photograph; possible microcrystalline quartz (SiO₂)

Tumbled fossil shark tooth pendant

Likely fossilized shark tooth, possibly Otodus or Carcharhinus; exact species cannot be confirmed from the image

Vesicular basalt (likely scoriaceous basalt)

Mafic volcanic rock, chiefly plagioclase, pyroxene, and olivine; commonly iron-rich volcanic glass

Polished greenstone/serpentine pebble (probable)

Serpentinite, dominated by serpentine-group minerals (lizardite/chrysotile); possible accessory olivine or chlorite

Tumbled blue-gray mineral specimen

Indeterminate; possibly dumortierite quartz, sodalite, or dyed stone

Tumbled or rough turquoise-like specimen

Turquoise, hydrated copper aluminum phosphate — CuAl₆(PO₄)₄(OH)₈·4H₂O; identification is uncertain from the image

Black glassy volcanic rock, likely scoria or obsidian

Vesicular basaltic scoria (probable); possibly dark obsidian

Likely rose quartz

Quartz, silicon dioxide (SiO₂), pink variety

Amethyst crystal cluster

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation

Polished turquoise-like stone

Likely turquoise, hydrated copper–aluminum phosphate: CuAl₆(PO₄)₄(OH)₈·4H₂O; identification is uncertain from the photo

Chert or flint nodule

Microcrystalline quartz (SiO₂), commonly chalcedony with possible iron-oxide staining

Polished orbicular basalt (likely)

Basalt, a fine-grained mafic volcanic rock; dark circular features may be amygdales or orbicules

Tumbled coral fragment (likely white calcitic coral)

Calcium carbonate, primarily aragonite or calcite (CaCO₃); exact coral genus cannot be determined from the image

Botryoidal chalcedony (possibly common opal)

Microcrystalline quartz, SiO₂; pale portions may include hydrated silica opal, SiO₂·nH₂O

Quartzite

Quartzite (SiO2)

Polished green-and-white stone, likely serpentine or nephrite jade

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

Gravel / Crushed Stone

Aggregate (mixed mineral rock fragments)

Serpentine

Hydrous magnesium iron silicate, (Mg,Fe)3Si2O5(OH)4

Limestone

Calcite (CaCO3)