Igneous, Sedimentary, Metamorphic, Mineral, Gemstone, Fossil, Or Meteorite

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Sandstone Concretion

Clastic Sedimentary Concretion (typically Quartz/Silica with Iron Oxide)

Peridot

Olivine ((Mg, Fe)2SiO4)

Sandstone Concretion

Ferruginous Sandstone Concretion

Quartz

Silicon dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz (Milky Variant)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Ironstone Concretion

Siderite or Hematite-bonded Concretion

Quartz

Silicon Dioxide (SiO2)

Ironstone concretion / Limonitic Sandstone

Goethite/Hematite Cemented Sandstone (Hydrated Iron Oxide)

Ironstone Concretion

Siderite or Hematite Concretion (FeCO3 or Fe2O3)

Quartz Crystal Fragment

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz (Smoky Quartz)

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Sandstone with Ironstone Concretion

Arenite with Hematite/Goethite nodules (Fe2O3 / FeO(OH))

Quartz

Silicon Dioxide (SiO2)

Likely polished basalt or iron-rich metamorphic rock

Basaltic rock, chiefly plagioclase and pyroxene; exact identification requires testing

Quartz with Iron Oxide Staining

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Weathered iron-rich concretion or ironstone cobble

Limonite/goethite-rich ironstone, commonly with hematite and quartz

Citrine and Quartz

Silicon Dioxide (SiO2)

Blue Apatite

Calcium phosphate mineral, Ca5(PO4)3(F,Cl,OH)

Tumbled dark quartzite or basalt pebble

Likely fine-grained basalt (plagioclase–pyroxene), though quartzite is possible from the image

Olivine (Peridot)

(Mg,Fe)2SiO4

Quartz

Silicon Dioxide (SiO2)

Olivine (Peridot)

(Mg,Fe)2SiO4

Quartz

Silicon Dioxide (SiO2)

Quartz (Quartzite / Iron-stained Quartz)

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)