Organic Gemstone (Fossilized Resin)

Fossilized Shark Tooth (Otodus obliquus)

Otodus obliquus (Mineralized Apatite / Bio-apatite)

Fossil gastropod shell

Fossilized marine gastropod; exact genus/species requires locality and examination

Fossilized wood (petrified wood)

Silicified fossil wood; commonly quartz/chalcedony (SiO₂) replacing wood

Possible fossilized bone fragment

Fossil bone, composition primarily carbonate-hydroxylapatite [Ca₅(PO₄)₃(OH)]

Fossilized Coral (Petoskey Stone / Favosites)

Hexagonaria percarinata / Favosites sp. (Calcite, CaCO3)

Fossilized Echinoid / Sea Urchin Internal Mold

Echinoidea internal cast (steinkern)

Turquoise

Hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O

Tree agate (dendritic agate)

Microcrystalline quartz (SiO₂) with manganese- or iron-oxide dendrites

Mixed tumbled gemstone chips

Polychrome jasper, quartz/chalcedony, feldspar, and other silicate fragments (exact identification requires testing)

Fossilized Dinosaur Skull (Tyrannosaurus rex)

Tyrannosaurus rex (permineralized fossil), rich in Hydroxylapatite/Silica

Tumbled turquoise

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

Turquoise carving

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

Tiger’s-eye

Chatoyant quartz (SiO₂), typically pseudomorphous quartz after crocidolite

Jasper

Silicon dioxide (SiO2)

Dendritic Opal

Hydrated Silica (SiO2·nH2O) with Manganese or Iron Oxide inclusions

Kambaba Jasper

Stromatolite

Tumbled turquoise

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

Tree Agate

Silicon Dioxide (SiO2) with Dendritic Inclusions

Opal cabochon or opal-like decorative specimen

Hydrated amorphous silica, SiO₂·nH₂O; likely synthetic or assembled opal material

Fossilized tooth, likely shark tooth

Fossilized selachian tooth; possibly a worn Otodus or related shark tooth

Coal (likely bituminous coal)

Bituminous coal; predominantly carbon with organic macerals and minor clay/pyrite

Fossil Shell (Bivalve)

Class Bivalvia (Likely a member of the Ostreidae or Gryphaeidae family), CaCO3

Polished yellow-orange chalcedony (likely carnelian or yellow agate)

Microcrystalline quartz, SiO₂; chalcedony variety

Fossilized Shark Tooth (Partial)

Elasmobranchii (fossil tooth fragment)

Montana Moss Agate

Chalcedony (Silicon Dioxide, SiO2)

Brecciated Jasper / Fossiliferous Jasper Egg

Cryptocrystalline Quartz (SiO2) with iron oxides and mineral inclusions

Fossiliferous shale or slate with plant impressions

Carbonaceous mudstone/shale; possible fossil plant material (often fern-like impressions)

Fossil Coral (Rugosa or Solitary Coral)

Rugosa (Order), often referred to as 'Horn Coral' (Lithostrotionella or Grewingkia)

Turquoise

Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]

Weathered fossil fragment, possibly bone

Indeterminate fossilized bone; likely mineralized vertebrate bone (apatite-rich)

Turquoise

Hydrated phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O

Chrysocolla in Malachite

Cu2CO3(OH)2 (Malachite) / Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O (Chrysocolla)

Petrified Wood

Silicified Wood (SiO2)

Tumbled turquoise-colored agate or chalcedony

Cryptocrystalline quartz (SiO₂), possibly dyed chalcedony; exact identification requires testing

Carnelian (orange chalcedony), possibly fire agate

Microcrystalline quartz, SiO₂ (chalcedony variety)

Bivalve seashell (likely cockle or ark clam)

Calcareous shell composed chiefly of aragonite (CaCO₃); exact species cannot be determined confidently from the image

Fossilized Coral

Cnidaria (Hexacorallia)

Polished chalcedony (likely sagenite or included agate)

Microcrystalline quartz, SiO₂, with iron-oxide and possibly rutile/goethite inclusions

Orange tumbled carnelian (likely)

Cryptocrystalline chalcedony, SiO₂; orange color commonly caused by iron oxides

Polished carnelian agate

Chalcedony (microcrystalline quartz), SiO₂, colored mainly by iron oxides

Petrified Wood

Silicified Wood (SiO2)

Polished tiger’s-eye-rich ironstone

Tiger’s eye (quartz, SiO₂) with limonite/goethite and iron-oxide bands