Hauyne

Hauyne is a tectosilicate mineral with the chemical formula Na3Ca(SiO4)F. It is a member of the sodalite group and is typically found in igneous rocks, particularly in nepheline syenites and phonolites. Hauyne is named after the German mineralogist Johann Friedrich Hauy, who first described the mineral in 1822.

Hauyne crystals are usually colorless or white, but they can also be pink, yellow, or green due to the presence of impurities. The mineral has a hardness of 5.5 to 6 on the Mohs scale and a specific gravity of approximately 2.6. It has a monoclinic crystal system and typically forms prismatic crystals with a tabular habit.

Hauyne is an important mineral in the petrogenesis of alkaline igneous rocks. It is often associated with other minerals such as nepheline, sodalite, and cancrinite. The mineral has also been found in meteorites, where it is believed to have formed during the early stages of the solar system's formation.

Hauyne has been used in the past as a source of fluorine, but its use in this capacity has declined due to the availability of other fluorine-bearing minerals. The mineral is also used in the production of ceramics and glass, where it acts as a flux and helps to lower the melting point of the materials.