quartzkristal
Quartzkristal is a term that appears to be a non-standard or possibly misspelled variation of "quartz crystal." Quartz is a mineral composed of silicon and oxygen atoms in a continuous framework of SiO4 silicon–oxygen tetrahedra, with the overall chemical formula SiO2. It is one of the most abundant minerals in the Earth's crust. Natural quartz crystals are often hexagonal prisms terminated by a pyramid on one or both ends. They can occur in a wide range of colors, depending on impurities present, and are known for their hardness and piezoelectric properties.
Quartz crystals have a long history of use by various cultures for both practical and decorative purposes.