Mineral, Possibly Rock Fragment Containing A Mineral

Tumbled pale quartz/chalcedony fragment

Quartz (SiO₂), possibly microcrystalline chalcedony

Conglomerate

Conglomerate (SiO2 matrix with various silicate clasts)

Fossiliferous Sandstone / Fossil Fragment

Fossiliferous Sedimentary Matrix with Indeterminate Fossil Material

Aggregate Concrete

Anthropogenic Conglomerate (Technosol)

Breccia

Breccia (Clastic Sedimentary Rock)

Basalt with Xenolith

Extrusive Igneous Rock containing Mantle Xenolith

Pyrite (iron pyrite)

Iron sulfide, FeS₂; commonly called fool’s gold

Likely tumbled sandstone or limestone

Quartz-rich sandstone (possibly calcarenite/limestone)

Shale

Argillite / Shale

Sandstone (with Limonite staining)

Arenite (primarily SiO2 with FeO(OH)·nH2O)

Clear quartz (likely quartz crystal fragment)

Quartz, silicon dioxide (SiO₂)

Chert Conglomerate (or Breccia)

Sedimentary Clastic Rock (variety: Ferruginous Chert Breccia)

Sandstone

Arenite (SiO2 primarily)

Sandstone

Arenite

Sandstone

Arenite (SiO2 based typically)

Likely weathered brown rock fragment

Indeterminate; possibly basaltic or iron-stained mafic rock

Peridotite (Olivine Rock)

Peridotite (composed largely of olivine, (Mg, Fe)2SiO4)

Not a rock, mineral, or geological specimen

Milky Quartz

Silicon Dioxide (SiO2)

Likely schist, possibly serpentinite

Mica schist; potential chlorite–serpentine-rich metamorphic rock

Sandstone

Arenite (SiO2 based)

Sandstone (Fossiliferous)

Clastic Sedimentary Rock (primarily SiO2)

Sandstone (Quartzose Sandstone)

Arenite

Sandstone

Arenite

Possible fossilized shell or coral fragment

Indeterminate biogenic carbonate, likely calcite (CaCO₃)

Sedimentary Rock (Limestone or Siltstone pebble)

Sedimentary rock fragment

Likely weathered limestone or calcareous tuff

Calcite-rich carbonate rock, chiefly CaCO₃; exact identification is uncertain from the image

Sodalite-bearing rock, likely sodalite-rich syenite or sodalite in feldspathic matrix

Sodalite, Na₈(Al₆Si₆O₂₄)Cl₂, with probable feldspar and accessory minerals

Fossiliferous Limestone (Coquina)

Calcite (CaCO3) with Bioclastic inclusions

Likely limestone or calcareous fossil fragment

Calcite-rich carbonate rock; possibly bioclastic limestone (CaCO₃)

Granite

Intrusive Igneous Rock

Granite

Intrusive Igneous Rock

Sandstone

Arenite

Sandstone

Arenite (lithic or quartz sandstone)

Granite fragment

Granite (Felsic Plutonic Rock)

Sandstone

Arenite (SiO2 principal)

Vesicular quartz-rich rock, possibly weathered rhyolite or hydrothermal quartz

Likely quartz (SiO₂) with altered feldspar, iron oxides, and cavities; exact identification requires testing

Dark flint or chert fragment

Microcrystalline quartz (SiO₂), commonly called flint when dark and nodular

Sandstone

Arenite (primarily SiO2)

Quartz Geode Fragment

Silicon dioxide (SiO2) within a nodule

Sandstone (Ferruginous)

Arenite (Fe-rich)

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