Organic Gemstone (Not A Rock Or Mineral In The Traditional Sense, But Bio Mineralized Material)

Petrified Wood

Silicified Wood (mainly Quartz/Chalcedony, SiO2)

Agate (Moss or Green Agate)

Silicon Dioxide (SiO2)

Pearls

Pearl: biomineralized aragonite (CaCO₃) and conchiolin

Fossilized Shark Tooth

Chondrichthyes tooth

Carnelian

SiO2 (Silicon Dioxide), a variety of Chalcedony

Jasper (Brown Iron-Rich Variety)

Silicon Dioxide (SiO2) with Fe2O3 (Iron Oxide/Crystalline Quartz)

Quartz

Silicon Dioxide (SiO2)

Jasper

Microcrystalline Quartz (SiO2)

Chert (Septarian or Nodular variety)

Microcrystalline Quartz (SiO2)

Dinosaur Claw Fossil

Fossilized Theropod Claw (Vertebrate Palaeontological Specimen)

Tumbled amber

Fossilized tree resin; predominantly polymerized diterpenoid resin (succinite when Baltic-type)

Ironstone Concretion / Goethite-Hematite Geode

Goethite / Hematite Concretion (Fe3O4 / FeO(OH) / Fe2O3)

Graphite-bearing schist (probable)

Graphite schist; chiefly quartz, mica, and graphite

Amber jewelry (possibly amber-colored glass or resin)

Amber — fossilized plant resin, chiefly composed of polymerized terpenoids; the pictured material cannot be confirmed from the image

Sandstone (with potential fossil inclusions)

Clastic sedimentary rock (primarily SiO2)

Limonite-stained Chert

Silicon Dioxide (SiO2) with Hydrated Iron Oxide (FeO(OH)·nH2O)

Petrified Wood

Silicified Wood (primarily SiO2)

Petrified Wood (Silicified Wood)

Silicified Wood / Silicon Dioxide (SiO2)

Polished amber-like organic gemstone

Amber (fossilized tree resin), commonly succinite; exact identification is uncertain from the image

Fossil Coral

Scleractinia or Anthozoa (Fossilized)

Vesicular quartz-rich rock, possibly weathered rhyolite or silicified volcanic breccia

Silica-rich volcanic rock; likely microcrystalline quartz (SiO₂) with altered feldspar and iron-oxide staining

Seashell Fossil

Invertebrate fossil (phylum Mollusca)

Amber-set ring

Amber (fossilized plant resin; organic mineraloid), set in a metal ring

Smoky Quartz

Silicon Dioxide (SiO2)

Blue Chalcedony

Chalcedony (SiO2)

Sandstone (Red / Iron-stained)

Sandstone (composed predominantly of SiO2 with Fe2O3 cement)

Yellow Jade (often Serpentine or Dolomite)

Primarily Serpentine (Mg3Si2O5(OH)4) or Dolomite (CaMg(CO3)2), though the term 'yellow jade' is also sometimes applied to varieties of true nephrite or jadeite.

Likely weathered quartz or feldspar grain

Uncertain; possibly quartz (SiO₂) or a feldspar mineral

Sandstone (River Cobble)

Clastic sedimentary rock (primarily SiO2)

Chert (with Quartz Vein)

Chert (Siliceous sedimentary rock, predominantly Microcrystalline Quartz SiO2)

Banded sandstone pebble

Quartz-rich lithic sandstone; exact provenance and composition require testing

Rose Quartz

Silicon Dioxide (SiO2)

Polished agate pebble

Banded chalcedony, a microcrystalline variety of quartz (SiO₂)

Chalcedony in Matrix (likely Agatized Coral or Chert)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 cement)

Iron-rich metamorphic rock (probable limonite/goethite-bearing schist)

Quartz–mica schist with iron oxyhydroxides, chiefly goethite (FeO(OH)) and limonite (amorphous hydrated iron oxides)

Petrified Wood

Silicified wood (Quartz replacement of organic wood structure)

Banded Chert / Sandstone Pebble

Microcrystalline Quartz (SiO2) / Silicified Sandstone

Hagstone (Adder Stone)

Chert or Sedimentary pebble with natural perforation

Pearl

Aragonite (CaCO3) with Conchiolin

Pink Dyed Agate Geode Slice

Silicon Dioxide (SiO2) with artificial pigment

Amber

Fossilized tree resin (Amorphous organic polymer)