Fenster Quartz Silicon Dioxide: SiO2 Mohs: 7 Chakra: Crown. Fenster quartz gets its name from the interior skeletal structure which has created many windows and chambers within the crystal. The name is derived from the German word "Fenster", meaning window. The crystals have grown in a very similar formation as a Herkimer diamond in combination with elestial formations. For this reason, these crystals are also known as Elestial Lightkeepers. Fenster Quartz is quite complex and high in vibrational stimulating the third eye and crown chakras. Meditation with these crystals can assist you to move through time and space like portals to other dimensions which is believed to facilitate deep karmic work with past lives. Fenster crystals are excellent facilitators during any healing sessions.