Sedimentary Rock Or Mineral (Depending On Origin And Purity)

Milky quartz

Quartz (SiO₂), likely massive vein quartz

Blue gemstone in a decorative setting (possibly blue spinel or sapphire)

Unidentified blue faceted gemstone; sapphire is corundum (Al₂O₃), while spinel is MgAl₂O₄

Sandstone

Sedimentary Rock (Quartz Arenite)

Sandstone (Pebble/Cobble)

Sandstone (arenite is a more precise term for sandstone with less than 15% matrix; this specimen appears to be a lithic or quartz arenite)

Quartz (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Natural gold nuggets

Native gold (Au)

River Pebble (Siltstone / Fine-grained Sandstone)

Sedimentary Pebble (Siliclastic)

Likely weathered limestone fragment

Calcite-rich limestone (CaCO₃), possibly calcareous sandstone

Small iron-oxide-rich rock fragment (possibly ferruginous sandstone)

Ferruginous sandstone or ironstone; likely quartz grains cemented by iron oxides such as hematite/goethite

Pyrite on Quartz matrix

Iron Disulfide (FeS2) on Silicon Dioxide (SiO2)

Sandstone

Sedimentary Rock (Quartz arenite / Lithic sandstone)

Sandstone

Arenite (SiO2 based)

Small rounded pebble, likely basalt

Fine-grained mafic volcanic rock (likely basalt); image alone cannot confirm composition

Xenolith in Basalt

Mafic Igneous Rock with Felsic Inclusion

Jasper Agate (Carnelian Jasper)

Silicon Dioxide (SiO2) with iron oxide inclusions

Diamond (Princess Cut)

Carbon (C)

Pink Quartzite

Quartzite (SiO2)

Sandstone

Arenite

Sandstone

Sandstone (SiO2 dominated clastic sedimentary rock)

Sandstone (with Liesegang rings or Oxidation)

Arenite (primarily Quartz SiO2 with Iron Oxide Fe2O3 staining)

Weathered iron-rich rock, possibly limonite-bearing basalt or ironstone

Indeterminate; likely Fe-oxide/hydroxide–stained basalt or ferruginous ironstone (goethite/limonite-rich)

Black beach pebble (likely basalt)

Fine-grained basalt; exact identification cannot be confirmed from the image

Quartz

Silicon Dioxide (SiO2)

Green Fluorite

Fluorite (Calcium Fluoride) - CaF2

Quartz Boulder

Silicon Dioxide (SiO2)

Conglomerate

Conglomerate (a clastic sedimentary rock)

Sandstone

Arenite (primarily SiO2, silica)

Weathered porphyritic volcanic rock (likely basaltic andesite)

Porphyritic basaltic andesite; mineral assemblage likely plagioclase, pyroxene, and iron oxides

Sandstone (likely Red/Brown Sandstone)

Arenite (SiO2 based)

Emerald

Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities

Quartz (Chalcedony)

Silicon Dioxide (SiO2)

Hematite Concretion

Iron(III) oxide (Fe2O3)

Shark Tooth Fossil

Vertebrate fossilized tooth

Quartz-rich foliated rock, possibly milky quartz vein material

Likely quartz-rich metamorphic rock; exact identification is uncertain from the image

Fluorite

Calcium Fluoride (CaF2)

Banded gneiss pebble

Gneiss, typically quartz–feldspar–mica assemblage

Fossilized Bone Fragment

Vertebrate Fossil

Fluorite

Calcium Fluoride (CaF2)

Likely basalt or another dark, coarse-grained igneous rock

Possibly olivine-bearing basalt (plagioclase, pyroxene, and possibly olivine); identification is uncertain from the photo

Speckled feldspar-rich pebble

Likely leucocratic granite or granitic pegmatite, chiefly potassium feldspar with dark biotite or amphibole

Drill-core rock, likely foliated metamorphic rock

Indeterminate from the photograph; possibly slate, phyllite, or schist

Sandstone (with Arkose characteristics)

Clastic sedimentary rock (SiO2 with KAlSi3O8)