What is a xenocryst?

A xenocryst is defined as a "foreign crystal" that is brought to the surface by magma. This term derives from the Greek words "xenos," meaning foreign, and "crystos," meaning crystal. Xenocrysts originate from pre-existing rocks or minerals that are incorporated into the magma during its ascent through the Earth's crust. As the magma cools and solidifies, these foreign crystals become part of the resulting igneous rock.

Understanding this concept is crucial in geology and gemology, as it helps to identify the origins and formation processes of various gemstones and minerals found in volcanic contexts. Xenocrysts can provide valuable information about the conditions under which the magma formed and the geological history of the area.