Althausite is a relatively simple

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...

phosphate mineral Phosphate minerals contain the tetrahedrally coordinated phosphate (PO43−) anion along sometimes with arsenate (AsO43−) and vanadate (VO43−) substitutions, and chloride (Cl−), fluoride (F−), and hydroxide (OH−) anions that also fit ...

with formula Mg₂(PO₄)(OH,F). It is very rare. Original occurrences are magnesite deposits among

serpentinite Serpentinite is a rock composed predominantly of one or more serpentine group minerals, the name originating from the similarity of the texture of the rock to that of the skin of a snake. Serpentinite has been called ''serpentine'' or ''se ...

s. It is named after Egon Althaus (born 1933), a mineralogist at the University of Karlsruhe, Germany.http://www.handbookofmineralogy.org/pdfs/althausite.pdf Handbook of Mineralogy

References

Magnesium minerals Phosphate minerals Orthorhombic minerals Minerals in space group 62 {{phosphate-mineral-stub