antecryst

Antecryst is a term used in geology to describe a crystal that forms before the main crystal of a mineral. This phenomenon occurs when a crystal begins to grow in a specific orientation, but the conditions change, causing the crystal to grow in a different direction. The result is a crystal that has two distinct growth orientations, with the earlier growth forming the "antecryst" and the later growth forming the main crystal. The antecryst is often smaller and less well-formed than the main crystal, and it may be oriented at an angle to the main crystal. Antecrysts are commonly found in minerals such as quartz, calcite, and feldspar, and they can provide valuable information about the conditions under which the mineral formed. The study of antecrysts is an important area of research in geology, as they can help scientists understand the processes that occur during crystal growth and the conditions that exist in the Earth's crust.