Mineraloid (Human Made Geological Specimen)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Blue Goldstone

Aventurine Glass (SiO2 with Cobalt/Copper inclusions)

Quartzite

Quartzite (primarily SiO2)

Bornite (“peacock ore”), likely weathered copper sulfide

Bornite, Cu₅FeS₄; possibly chalcopyrite, CuFeS₂, with iridescent tarnish

Granite

Felsic intrusive igneous rock

Aventurine Quartz

Silicon Dioxide (SiO2) with Fuchsite inclusions

Tumbled pale green calcite

Calcite (CaCO₃)

Rounded quartz-rich cobble

Likely quartzite or siliceous sandstone; predominantly microcrystalline SiO₂ with possible feldspar and iron-oxide staining

Chalcopyrite

Chalcopyrite (CuFeS2)

Quartz with Pyrite

Silicon Dioxide (SiO2) with Iron Sulfide (FeS2)

Milky quartz (likely weathered quartz vein)

Quartz, silicon dioxide (SiO₂)

Red calcite

Calcite (CaCO₃), likely iron- or manganese-colored

Quartz (Milky/Vein Quartz)

Silicon Dioxide (SiO2)

Basalt

Basalt (Mafic volcanic rock)

Ferruginous Quartz

Silicon Dioxide (SiO2) with Limonite/Hematite inclusions

Weathered quartz-rich pebble (probable quartzite or quartz vein fragment)

Quartzite, predominantly silicon dioxide (SiO₂); exact identification is uncertain from the photograph

Tumbled reddish sandstone pebble

Quartz-rich sandstone, likely ferruginous arkose or quartz arenite

Fossiliferous Limestone (with Rugose Coral)

Limestone with Tetracoralla (Rugosa) fossil

Gold (in Opaque Matrix/Jewelry)

Native Gold (Au)

Botryoidal Agate

Chalcedony (Silicon Dioxide, SiO2)

Tumbled dark stone, likely basalt or basaltic rock

Fine-grained mafic volcanic rock; commonly basalt, composed chiefly of plagioclase and pyroxene with possible olivine and iron oxides

Chalcedony (Agate/Carnelian variant)

Silicon Dioxide (SiO2)

Blue Chalcedony

Chalcedony (Silicon Dioxide, SiO2)

Sandstone

Arenite (primarily SiO2)

White Marble

Recrystallized Calcite (CaCO3)

Sandstone

Arenite (composed primarily of SiO2)

Amber

Succinite

Quartz

Silicon Dioxide (SiO2)

Red Jasper

Silicon Dioxide with iron impurities (Quartz variety, SiO2)

Glacial Cobble with Granite Inclusion

Porphyritic Basalt or Andesite containing Granitic Xenolith

Brown quartz-rich stone, possibly smoky quartz or quartzite

Quartz (SiO₂), potentially in a quartzite or silica-rich matrix

Cordierite in Matrix (Iolite)

Magnesium iron aluminium cyclosilicate (Mg,Fe)2Al4Si5O18

Green Fluorite

Fluorite (Calcium Fluoride, CaF2)

Quartz with Iron Oxide Inclusions

SiO2 with Fe2O3 impurities

Coal (Bituminous Coal)

Caustobiolith / Sedimentary Rock

Limonite and Goethite on Gossan

FeO(OH)·nH2O

Faceted Glass (Costume Jewelry)

Amorphous Silicon Dioxide with colorants (Glass)

Milky quartz fragment

Quartz (silicon dioxide, SiO₂)

Coquina / Fossiliferous Limestone

Calcareous bioclastic sedimentary rock (CaCO3)

Quartz Pebble

Silicon Dioxide (SiO2)

Pink Granite (Gneissic Granite)

Granite (composed primarily of Quartz, K-Feldspar, and Plagioclase)

Granite Pebble (Pink Granite)

Phaneritic Igneous Rock (primarily Quartz, Potassium Feldspar, and Plagioclase)