Igneous (Anthropogenic)

Granite

Granite (composed of Quartz, Feldspar, and Mica)

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Magnetite

Fe3O4 (Iron(II,III) oxide)

Granite / Feldspar gravel

Granite (felsic intrusive igneous rock)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz (Raw and Water-worn)

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz with Muscovite Mica

Silicon Dioxide (SiO2) with Potassium aluminum silicate hydroxide fluoride [KAl2(AlSi3O10)(F,OH)2]

Milky Quartz with inclusions

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz Druze (Crystalline Quartz)

Silicon Dioxide (SiO2)

Quartz (Milky and Smoky variety)

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Gabbro

Gabbro

Gabbro (Water-worn Pebble)

Gabbro

Granite and Igneous Mix

Phaneritic Felsic to Mafic Intrusive Rocks

Sodalite

Sodalite (Na8(Al6Si6O24)Cl2)

Magnetite (Lodestone)

Magnetite (Fe3O4)

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Likely porphyritic igneous rock (possibly granite or rhyolite)

Quartz–feldspar–mica aggregate; exact identification requires a fresh surface and tests

Possible dark igneous rock

Indeterminate; likely basalt or fine-grained mafic rock

Banded Igneous Dike Rock

Intrusive igneous rock with felsic/mafic banding

Porphyritic Igneous Rock / Basalt or Andesite Xenolith in Granite or Quartzite

Silicate rock with contrasting xenolith/inclusion

Weathered igneous rock fragment, possibly granite or granitic gneiss

Indeterminate; likely quartz–feldspar–mica aggregate (granite), possibly foliated gneiss

Granite-like igneous rock

Likely medium-grained granite or granodiorite; quartz–feldspar–mica aggregate

Porphyritic Igneous Rock / Rhyolite Porphyry

Porphyritic volcanic rock

Porphyritic Igneous Rock / Granite or Rhyolite Porphyry

Porphyritic intrusive/extrusive igneous rock

Porphyritic Igneous Rock / Porphyry

Porphyry (Plagioclase/Quartz phenocrysts in a finer-grained groundmass)

Granite

Intrusive Igneous Rock

Granite

Intrusive Igneous Rock

Basalt

Extrusive Igneous Rock

Basalt Pebble

Extrusive Igneous Rock

Basalt

Extrusive Igneous Rock

Basalt Pebble

Extrusive Igneous Rock

Basalt

Extrusive Igneous Rock

Basalt

Extrusive Igneous Rock

Granite

Intrusive Igneous Rock

Basalt

Extrusive Igneous Rock

Basalt

Extrusive Igneous Rock

Granite

Intrusive Igneous Rock