Anthropogenic (Man Made Industrial Byproduct)

Tumbled green aventurine (probable)

Quartzite dominated by quartz (SiO₂), with green mica/fuchsite or chlorite inclusions

Gold

Native Gold (Au)

Quartz (Float/Abraded)

Quartz (SiO₂)

Vesicular Basalt (commonly mistaken for Slag)

Scoriaceous Basalt (composed primarily of Plagioclase Feldspar and Pyroxene)

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

Fossiliferous Limestone

Limestone (composed primarily of calcite with included fossils CaCO3)

Calcite

Calcium Carbonate (CaCO3)

Wollastonite

Calcium Inosilicate, CaSiO3

Rounded gray river pebble, likely basalt or andesite

Fine-grained mafic volcanic rock; commonly basalt (plagioclase, pyroxene, and possible olivine)

Botryoidal Chalcedony

Chalcedony (SiO2)

Asphalt aggregate (crushed stone in bitumen)

Artificial composite; predominantly crushed granite, basalt, limestone, and/or recycled aggregate bound by bitumen

Silver (Sterling Silver Jewelry)

Argentum (Ag) mixed with Copper (Cu)

Granite

Granite (a common rock name, not a single mineral species, composed primarily of quartz, feldspar, and mica/amphibole)

Weathered iron-rich rock, likely basalt or ironstone

Probable weathered basalt (mafic silicate rock); exact identification requires a fresh surface and testing

Calcite

Calcite (CaCO3)

Concrete or asphalt-like aggregate surface with a dark fragment

Uncertain; likely artificial concrete containing mixed lithic aggregate, not a natural rock

Pebble (likely Quartz or Chert)

SiO₂ (Silicon Dioxide) - referring to the likely main mineral composition, Quartz. If it's chert, the scientific name remains SiO₂ with a microcrystalline structure.

Pearl (Biogenic Mineraloid)

Calcium carbonate (CaCO3) primarily as Aragonite

Queen Conch Shell (Biogenic Calcium Carbonate)

Aliger gigas (synonym Strombus gigas); Composition: Aragonite (CaCO3)

Weathered dark rock fragment

Indeterminate; possibly basalt or iron-rich volcanic rock

Iron meteorite fragment (probable)

Fe–Ni metallic meteorite, commonly octahedrite (kamacite–taenite)

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Quartz Pebble

Silicon Dioxide (SiO2)

Vesicular basalt (likely scoria)

Basaltic volcanic rock; mainly plagioclase, pyroxene, and often olivine, with abundant gas vesicles

Likely hematite-rich ironstone or metallic mineral fragment

Hematite (Fe₂O₃), possibly with magnetite (Fe₃O₄) or metallic iron

Amethyst (variety of Quartz)

SiO2 (Silicon Dioxide) with trace iron impurities

Chert

Chert (Microcrystalline Quartz)

Likely black beach pebble

Undetermined; possibly basalt, chert, or dark slate

Likely galena-bearing ore

Galena (lead sulfide, PbS), possibly mixed with quartz or other sulfides

Quartz (in a rock matrix)

Quartz (SiO2)

Sandstone

Arenite (mostly SiO2)

Pearl

Calcium carbonate (CaCO3) - mainly Aragonite with Conchiolin

Sandstone

Arenite (with iron oxide cement)

Turquoise

CuAl6(PO4)4(OH)8·4H2O

N/A (Non-Geological Object)

Gypsum (Satin Spar / Alabaster variety)

Calcium Sulfate Dihydrate (CaSO4·2H2O)

Conglomeratic concrete or asphalt aggregate surface with dark bituminous chunks

Polymictic gravel aggregate; dark pieces likely bitumen/asphalt, not a natural rock

Quartzite

Metamorphic Quartzite (SiO2)

Limestone Pebble

Sedimentary Calcium Carbonate (CaCO3)

Quartzite

Metamorphic Quartz Rock (SiO2)

Sandstone

Arenite (SiO2 primarily)

Chalk

Carbonate rock (mainly CaCO3)