This image shows some of the most common minerals you'll find in rocks. This pile contains plagioclase feldspar , potassium feldspar , quartz , muscovite mica , biotite mica , amphibole , olivine , and calcite . Click on any mineral for a close up view. Quartz Quartz is one of the most common minerals in the Earth's crust. Plagioclase is a member of the feldspar mineral family.
Plagioclase feldspars are yet another silicate that contains considerable sodium or calcium.
Feldspar crystals are stubby prisms, generally white to gray and a glassy luster . This variety of plagioclase, called albite , is rich in sodium. Potassium feldspar Potassium feldspar is another member of the feldspar mineral family. Feldspar crystals are stubby prisms, often pink to white. Mica Micas are another group of silicate minerals composed of varying amounts of potassium, magnesium, iron as well as aluminum, silicon and water.