Sedimentary And Metamorphic

Unidentified Rock Fragment

Unknown

Mixed pebble collection, including likely flint, quartzite, and fossil material

Varied silicate rocks; visible specimen may include chert (microcrystalline SiO₂), quartzite, and a possible fossil

Tumbled orange chalcedony and a gray stone disk

Chalcedony (microcrystalline quartz, SiO₂); disk likely fine-grained sandstone or slate

Fluorite

Calcium Fluoride (CaF2)

Clear calcite cleavage fragment

Calcite (calcium carbonate, CaCO₃)

Pyrite-bearing rock (iron pyrite)

Pyrite, FeS₂, likely disseminated or massive in a host rock

Polished malachite

Malachite, Cu₂CO₃(OH)₂

Red Jasper

Silicon Dioxide (SiO2) with Hematite impurities

Jasper

Jasper (Silicon Dioxide, SiO2)

Jasper (Red Jasper)

Silicon Dioxide (SiO2) with Hematite inclusions

Tumbled quartz-rich pebble

Microcrystalline quartz (SiO₂), possibly milky quartz or chalcedony

Green calcite (probable)

Calcite, calcium carbonate (CaCO₃)

Fossil shark tooth

Likely fossilized shark tooth, possibly Carcharhinus or Otodus species

Pearl

Pearl; primarily aragonite (CaCO₃) in nacre

Pyrite-bearing rock (likely pyrite-rich quartz or schist)

Pyrite, FeS₂, intergrown with quartz and/or mica-rich matrix

Red Jasper

SiO2 (Silicon Dioxide with Iron inclusions)

Pearl-bearing oyster shell

Nacreous shell, primarily aragonite (CaCO₃), with natural pearls (calcium-carbonate nacre)

Desert rose

Gypsum (selenite) rosette, CaSO₄·2H₂O

Feldspar-rich Quartzite

Metamorphic Quartz-Feldspar Aggregate (SiO2 + KAlSi3O8)

Red Jasper (Opaque Chalcedony)

Silicon Dioxide (SiO2) with Hematite inclusions

Jasper

Silicon dioxide (SiO2)

Yellow-green serpentine (likely)

Serpentine-group phyllosilicate, commonly lizardite or antigorite; approximate formula Mg₃Si₂O₅(OH)₄

Pearl

Nacre (aragonite, CaCO₃, in an organic conchiolin matrix)

Limonite Pseudomorph after Pyrite

Goethite/Limonite FeO(OH)·nH2O replacing Pyrite FeS2

Banded calcite (likely cave deposit or vein fragment)

Calcite, CaCO₃

Tumbled amethyst

Amethyst, purple variety of quartz (SiO₂)

Sandstone or Quartzite

Arenite (if sedimentary) / Quartzite (if metamorphic)

Sandstone or Quartzite

Sandstone or Quartzite (SiO2 primarily)

Pearl necklace

Pearl—biogenic calcium carbonate, primarily aragonite (CaCO₃)

Likely anthracite coal fragments

Anthracite; predominantly carbon (C), with minor mineral ash

Shale or Slate

Shale (Sedimentary) or Slate (Metamorphic)

Weathered quartz-rich rock, likely chert or quartzite

Microcrystalline quartz (SiO₂), possibly with iron-oxide staining

Banded Chert / Banded Jasper (likely a variety of Chert/Chalcedony)

Chert (microcrystalline quartz)

Tumbled golden-brown stone, likely sandstone or iron-stained quartzite

Indeterminate from image; probable quartz-rich sandstone (SiO₂) or quartzite

Sandstone, Quartzite, and River Pebbles

Silicon Dioxide (SiO2) based Sedimentary/Metamorphic structures

Quartzite / Sandstone / Chert Mix

Silicon Dioxide (SiO2)

Tumbled reddish-brown pebble, likely sandstone or iron-rich quartzite

Probable ferruginous sandstone (quartz-rich; SiO₂ with iron oxides), possibly quartzite

Weathered iron-rich stone, possibly chert or quartzite

Indeterminate; likely silica-rich rock with iron-oxide staining (SiO₂-dominant)

Jasper

Chalcedony (Microcrystalline Quartz) - SiO2

Tumbled reddish-brown stone, possibly jasper or iron-rich quartzite

Uncertain from image; likely microcrystalline quartz (SiO₂) with iron-oxide inclusions

Sandstone or Quartzite pebble

Sandstone (Quartz arenite) or Quartzite

Quartz (chalcedony variety) or Limestone with Quartz Veins

SiO2 (for Quartz/Chalcedony); CaCO3 (for Limestone)