Nebenmineralien

Nebenmineralien, also known as accessory minerals, are mineral species that occur in igneous rocks in relatively small, non-essential amounts. Unlike the main or essential minerals that define a rock's classification, such as feldspar and quartz in granite, Nebenmineralien are present in quantities typically less than 5% by volume. Their presence is often a consequence of the specific conditions under which the rock formed, including the availability of certain elements and the pressure and temperature of the environment.

These minerals can provide valuable insights into the geological history and petrogenesis of the host rock. Their composition can reflect subtle variations in the magma's chemistry, such as the presence of trace elements or specific volatile components. For example, the occurrence of minerals like apatite, zircon, sphene, or opaques (magnetite, ilmenite) in an igneous rock are common examples of Nebenmineralien. They can also form during later alteration processes affecting the primary rock. While not determining the rock type, their identification and abundance can aid in detailed petrological studies and mineral exploration.