Phantomquartz

Quartz crystals with enclosed minerals such as chlorite or particles of shale dust are not only visually very attractive but also valuable data records. Since usually only the upward-facing surfaces were covered with additional minerals, the position of the crystals in the fissure can be reconstructed on the basis of these inclusions.

Photo: Phantom quartz (chlorite), Furka UR, collection Felix Spahr; not for sale.