Anthropogenic (Man Made Material Mimicking Sedimentary Rock)

Veined Quartz

SiO2 (Silicon Dioxide)

Weathered iron-rich rock, possibly laterite or limonite-bearing sandstone

Laterite/limonite-rich material; commonly dominated by goethite (FeO(OH)) and hydrated iron oxides

Red Jasper or Chert

Jasper (SiO2, a variety of chalcedony with iron oxide impurities), Chert (SiO2)

Weathered quartz-rich cobble (probable quartzite or silicified rock)

Quartzite, predominantly SiO₂; exact identification is uncertain from the photograph

Cullet Glass (Slag)

Amorphous Silicon Dioxide (Man-made)

Banded gneiss, probably granitic gneiss

Foliated gneiss composed mainly of quartz (SiO₂), feldspar—orthoclase/microcline and plagioclase—and dark mica, commonly biotite K(Mg,Fe)₃AlSi₃O₁₀(F,OH)₂

Banded Calcite (often sold as 'Mexican Onyx')

Calcite (Calcium Carbonate, CaCO3)

Fossil Coral

Fossilized Scleractinia or Tabulata (various genera/species)

Opalite

Synthetic glass / Opaque silicious glass

Quartzite

Quartzite (primarily SiO2)

Turquoise

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

Halite

Sodium Chloride (NaCl)

Sea Glass (Frosted Glass)

Amorphous Silica (SiO2) with various metal oxide impurities

Bumblebee Jasper

Fibrous Calcite and Quartz with Volcanic Matter (CaCO3 / SiO2)

Pyrite

Pyrite (FeS2)

Diamond (or Simulant)

Carbon (C)

Mookaite Jasper

Siliceous sedimentary rock (variety of Jasper/Chert)

Ocean Jasper

Silicon Dioxide (SiO2)

Coquina

Coquina (a type of limestone)

Quartz (likely macrocrystalline variety)

Quartz (SiO₂)

Travertine (used in construction, not a 'specimen' in situ)

Travertine

Opalite

Synthetic Opalite (Man-made glass)

Anthracite Coal

Anthracite (Carbon-based organic sedimentary rock transitioned to metamorphic)

Chert (varieties include Flint or Jasper)

Chert (cryptocrystalline quartz; SiO₂)

Weathered fossiliferous limestone fragment, possibly fossil coral or shell material

Indeterminate carbonate fossil in calcitic limestone; likely composed mainly of calcite (CaCO₃), but species identification is not possible from this image alone

Quartz (likely tumbled or naturally water-worn)

Quartz (SiO₂ - Silicon Dioxide)

Coal (most likely Bituminous or Anthracite)

Coal (primarily composed of carbon with varying amounts of other elements)

Weathered fossiliferous limestone or fossil fragment

Indeterminate bioclastic carbonate rock; likely calcite (CaCO₃) with fossil shell material

Tumbled gray-green pebble, likely chert or altered volcanic rock

Cryptocrystalline quartz (chert), possibly silicified volcanic material

Quartz (likely a weathered/tumbled piece)

Quartz (SiO₂)

Pyrite

Pyrite (Iron Disulfide), FeS2

Mixed collection of common river stones

Varied lithologies, visibly including quartz-rich rock, dark mafic rock, sandstone, and purple quartz-bearing material

Conglomerate

Conglomerate

Epidote in Quartz

Quartz with Epidote inclusions (SiO2 with Ca2(Al,Fe)3(SiO4)3(OH) inclusions)

Quartz

Quartz (SiO2 - Silicon Dioxide)

Quartz (likely Milky Quartz or Chalcedony)

Quartz (SiO2 - Silicon Dioxide)

Conglomerate

Conglomerate

Red Jasper

Jasper (a variety of Quartz, SiO2)

Calcite

Calcite (CaCO3)

Quartz with Basalt inclusion

Silicon Dioxide (SiO2) with mafic silicate rock

Quartz Geode/Cluster

Quartz (SiO2)

Pebble (likely Quartzite or Chert)

Clastic Sediment, potentially composed of SiO₂ (Quartz)