Igneous And Metamorphic Derivative (Weathered)

Orthoclase Feldspar

Orthoclase (KAlSi3O8)

Quartz (Grain)

Silicon Dioxide (SiO2)

Mixed rounded stream pebbles

Most appear to be granitic and mafic igneous rocks, including granite, gneiss, basalt, and possibly quartzite; exact identification is uncertain from the image.

Quartz

Silicon Dioxide (SiO2)

Magnetite-rich ironstone (probable magnetite ore)

Magnetite, Fe₃O₄, likely in a fine-grained ironstone matrix

Quartz-veined Metamorphic Pebble

Silicate-rich metamorphic rock with quartz veins (SiO2)

Quartz-rich rock fragment, possibly granite or quartzite

Primarily quartz (SiO₂), with possible feldspar and iron-oxide staining

Quartz with inclusions

SiO2

Quartz Pebble

Silicon Dioxide (SiO2)

Almandine Garnet

Almandine (Fe3Al2(SiO4)3)

Milky Quartz

Silicon Dioxide (SiO2)

Fossiliferous limestone (likely crinoidal or shell limestone)

Calcite-rich limestone; predominantly CaCO₃, with visible fossil fragments

Feldspar (likely Orthoclase or Plagioclase)

Tectosilicate Feldspar (KAlSi3O8 to (Ca,Na)(Al,Si)4O8)

Orange Quartz

Silicon Dioxide (SiO2) with Hematite inclusions

Likely weathered fossil shell or fossiliferous limestone

Indeterminate molluscan fossil, possibly a bivalve or brachiopod preserved in carbonate rock

Rounded reddish-brown river pebble

Indeterminate weathered silicate rock, possibly granite, rhyolite, or iron-stained quartzite

Weathered schist or gneiss fragment

Quartz–feldspar–mica metamorphic rock; likely mica schist or gneiss

Milky quartz

Quartz (silicon dioxide, SiO₂)

Weathered quartz-rich pebble

Likely quartz-bearing granite or granitic gneiss; exact identification requires testing

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Weathered metamorphic rock, likely gneiss or schist

Indeterminate foliated silicate rock; commonly quartz–feldspar–mica assemblage

Quartz Pebble

Silicon Dioxide (SiO2)

Granite Pebble on Flagstone

Granite (Felsic Plutonic Rock)

White quartz-rich pebble

Quartz (SiO₂), possibly milky quartz or quartzite

Quartz (Yellow / Citrine Quartz Pebble)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz (Field Stone)

Silicon Dioxide (SiO2)

Quartz Pebble (with potential iron inclusions)

Silicon Dioxide (SiO2)

Tumbled milky quartz (likely quartzite or quartz pebble)

Quartz, silicon dioxide (SiO₂); exact rock type is uncertain from the image

Likely iron-stained quartz or feldspar fragment

Quartz (SiO₂) or potassium feldspar (KAlSi₃O₈), uncertain from image

Ruby / Pink Sapphire

Corundum (Al2O3 with Chromium impurities)

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Corundum (Sapphire)

Corundum (Al2O3)

Milky Quartz with inclusions

Silicon Dioxide (SiO2)

Blue Sapphire

Corundum (Al2O3 with iron and titanium trace elements)

Likely biotite-bearing metamorphic rock (schist or gneiss)

Mica schist/gneiss; chiefly quartz, feldspar, and biotite mica

Rounded gray river pebble, likely basalt or andesite

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

Quartz Pebble

Silicon Dioxide (SiO2)

Grey Agate

Silicon Dioxide (SiO2) - Variety of Chalcedony

Weathered quartz-rich cobble, possibly quartzite or feldspar-rich granite

Quartz–feldspar aggregate; identification is uncertain from the photograph

Weathered banded metamorphic rock, likely gneiss

Banded gneiss; commonly quartz–feldspar–mica assemblage